diff --git a/.gitignore b/.gitignore
index 3c3629e6..ec685bab 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,5 @@
 node_modules
+implement-cowsay/.venv
+**/package.json
+**/package-lock.json
+implement-cowsay/requirements.txt
\ No newline at end of file
diff --git a/number-systems/README.md b/number-systems/README.md
deleted file mode 100644
index 77a3bde9..00000000
--- a/number-systems/README.md
+++ /dev/null
@@ -1,65 +0,0 @@
-Do not use any tools or programming to solve these problems. Work it out yourself by hand, and fill in the answers.
-
-Do not convert any binary numbers to decimal when solving a question unless the question explicitly tells you to.
-
-The goal of these exercises is for you to gain an intuition for binary numbers. Using tools to solve the problems defeats the point.
-
-Convert the decimal number 14 to binary.
-Answer:
-
-Convert the binary number 101101 to decimal:
-Answer:
-
-Which is larger: 1000 or 0111?
-Answer:
-
-Which is larger: 00100 or 01011?
-Answer:
-
-What is 10101 + 01010?
-Answer:
-
-What is 10001 + 10001?
-Answer:
-
-What's the largest number you can store with 4 bits, if you want to be able to represent the number 0?
-Answer:
-
-How many bits would you need in order to store the numbers between 0 and 255 inclusive?
-Answer:
-
-How many bits would you need in order to store the numbers between 0 and 3 inclusive?
-Answer:
-
-How many bits would you need in order to store the numbers between 0 and 1000 inclusive?
-Answer:
-
-How can you test if a binary number is a power of two (e.g. 1, 2, 4, 8, 16, ...)?
-Answer:
-
-Convert the decimal number 14 to hex.
-Answer:
-
-Convert the decimal number 386 to hex.
-Answer:
-
-Convert the hex number 386 to decimal.
-Answer:
-
-Convert the hex number B to decimal.
-Answer:
-
-If reading the byte 0x21 as a number, what decimal number would it mean?
-Answer:
-
-If reading the byte 0x21 as an ASCII character, what character would it mean?
-Answer:
-
-If reading the byte 0x21 as a greyscale colour, as described in "Approaches for Representing Colors and Images", what colour would it mean?
-Answer:
-
-If reading the bytes 0xAA00FF as an RGB colour, as described in "Approaches for Representing Colors and Images", what colour would it mean?
-Answer:
-
-If reading the bytes 0xAA00FF as a sequence of three one-byte decimal numbers, what decimal numbers would they be?
-Answer:
diff --git a/prep-sprint5/class-object-person.py b/prep-sprint5/class-object-person.py
new file mode 100644
index 00000000..a025ed0f
--- /dev/null
+++ b/prep-sprint5/class-object-person.py
@@ -0,0 +1,40 @@
+'''
+Run it through mypy - notice that no errors are reported - mypy understands 
+that Person has a property named age so is happy with the function.
+Write a new function in the file that accepts a Person as a parameter 
+and tries to access a property that doesn't exist. Run it through mypy 
+and check that it does report an error.
+'''
+
+class Person:
+    def __init__(self, name: str, age: int, preferred_operating_system: str):
+        self.name = name
+        self.age = age
+        self.preferred_operating_system = preferred_operating_system
+
+imran = Person("Imran", 22, "Ubuntu")
+print(imran.name)
+#print(imran.address)
+
+eliza = Person("Eliza", 34, "Arch Linux")
+print(eliza.name)
+#print(eliza.address)
+
+def is_adult(person: Person) -> bool:
+    return person.age >= 18
+
+print(is_adult(imran))
+
+''' adding the function:'''
+def read_genre(person: Person) -> str:
+    if person.genre == "M":
+        return "Male"
+    else:
+        return "Female"
+
+''' returns:
+cyf@cyfs-MacBook-Pro prep-sprint5 % mypy class-object-person.py   
+class-object-person.py:29: error: "Person" has no attribute "genre"  [attr-defined]
+Found 1 error in 1 file (checked 1 source file)
+
+'''
diff --git a/prep-sprint5/dataclass-person.py b/prep-sprint5/dataclass-person.py
new file mode 100644
index 00000000..c1c6a9ac
--- /dev/null
+++ b/prep-sprint5/dataclass-person.py
@@ -0,0 +1,27 @@
+'''Write a Person class using @datatype which uses a datetime.date for date of birth, 
+rather than an int for age.
+Re-add the is_adult method to it.'''
+from dataclasses import dataclass
+from datetime import date
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    date_of_birth: date
+    preferred_operating_system: str
+
+    def is_adult(self) -> bool:
+        today_year = date.today().year
+        birth_year = self.date_of_birth.year
+        age = today_year - birth_year
+
+        if date.today().month > self.date_of_birth.month:
+            return age >= 18
+        elif date.today().month == self.date_of_birth.month:
+            return date.today().day >= self.date_of_birth.day and age >= 18
+        else:
+            return age - 1 >= 18
+
+imran = Person("Imran", date(2002, 9, 21), "Ubuntu")
+print(imran)
+print("Is adult?", imran.is_adult())
\ No newline at end of file
diff --git a/prep-sprint5/enums.py b/prep-sprint5/enums.py
new file mode 100644
index 00000000..a288483e
--- /dev/null
+++ b/prep-sprint5/enums.py
@@ -0,0 +1,108 @@
+'''
+Write a program which:
+1.Already has a list of Laptops that a library has to lend out.
+2.Accepts user input to create a new Person - it should use the input function to 
+read a person's name, age, and preferred operating system.
+3.Tells the user how many laptops the library has that have that operating system.
+4.If there is an operating system that has more laptops available, tells the user 
+that if they're willing to accept that operating system they're more likely to get a laptop.
+
+You should convert the age and preferred operating system input from the user 
+into more constrained types as quickly as possible, and should output errors to 
+stderr and terminate the program with a non-zero exit code if the user input bad values.
+'''
+
+from dataclasses import dataclass
+from enum import Enum
+from typing import List
+
+class OperatingSystem(Enum):
+    MACOS = "macOS"
+    ARCH = "Arch Linux"
+    UBUNTU = "Ubuntu"
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    age: int
+    preferred_operating_system: OperatingSystem
+
+
+@dataclass(frozen=True)
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    screen_size_in_inches: float
+    operating_system: OperatingSystem
+
+
+def find_possible_laptops(laptops: List[Laptop], person: Person) -> List[Laptop]:
+    possible_laptops = []
+    for laptop in laptops:
+        if laptop.operating_system == person.preferred_operating_system:
+            possible_laptops.append(laptop)
+    return possible_laptops
+
+
+people = [
+    Person(name="Imran", age=22, preferred_operating_system=OperatingSystem.UBUNTU),
+    Person(name="Eliza", age=34, preferred_operating_system=OperatingSystem.ARCH),
+]
+
+laptops = [
+    Laptop(id=1, manufacturer="Dell", model="XPS", screen_size_in_inches=13, operating_system=OperatingSystem.ARCH),
+    Laptop(id=2, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system=OperatingSystem.UBUNTU),
+    Laptop(id=3, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system=OperatingSystem.UBUNTU),
+    Laptop(id=4, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system=OperatingSystem.MACOS),
+]
+
+print("Library laptops:") # 1. list of laptops
+for laptop in laptops:
+    print(f"- ID:{laptop.id} {laptop.operating_system.value} - {laptop.manufacturer} {laptop.model} Size: {laptop.screen_size_in_inches}")
+
+# receiving values from input to create person:
+name = input("Enter your name: ")
+age = int(input("Enter your age: "))
+
+print("Choose preferred operating system:")
+print("1. macOS")
+print("2. Arch Linux")
+print("3. Ubuntu")
+choice = input(">> ")
+
+os_map = {
+    "1": OperatingSystem.MACOS,
+    "2": OperatingSystem.ARCH,
+    "3": OperatingSystem.UBUNTU,
+}
+
+preferred_os = os_map.get(choice)
+
+person = Person(name=name, age=age, preferred_operating_system=preferred_os)
+
+print("Created person:", person)
+# counts how many laptops there are with that OS
+matches_count = sum(
+    1 for laptop in laptops
+    if laptop.operating_system == person.preferred_operating_system
+)
+print(f"There are {matches_count} laptop(s) with {person.preferred_operating_system.value}.")
+
+count_laptops_by_os = {
+    os_type: sum(1 for laptop in laptops if laptop.operating_system == os_type)
+    for os_type in OperatingSystem
+}
+
+best_os = max(count_laptops_by_os, key = count_laptops_by_os.get)
+best_os_count = count_laptops_by_os[best_os]
+
+if best_os != person.preferred_operating_system:
+    print(
+        f"There are more laptops available with {best_os.value} "
+        f"({best_os_count} laptops). If you're willing to use that OS, "
+        "you're more likely to get a laptop."
+    )
+else:
+    print("Good choice! Your preferred OS  has the highest availability.")
+
diff --git a/prep-sprint5/generics.py b/prep-sprint5/generics.py
new file mode 100644
index 00000000..c5fc7a94
--- /dev/null
+++ b/prep-sprint5/generics.py
@@ -0,0 +1,21 @@
+from dataclasses import dataclass
+from typing import List
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    age: int
+    children: List["Person"]
+
+fatma = Person(name="Fatma", age=20, children=[])
+aisha = Person(name="Aisha", age=30, children=[])
+
+imran = Person(name="Imran", age=50, children=[fatma, aisha])
+maria = Person(name="maria", age=38,children=[fatma])
+
+def print_family_tree(person: Person) -> None:
+    print(person.name)
+    for child in person.children:
+        print(f"- {child.name} ({child.age})")
+
+print_family_tree(maria)
\ No newline at end of file
diff --git a/prep-sprint5/inheritance.py b/prep-sprint5/inheritance.py
new file mode 100644
index 00000000..d6ebb623
--- /dev/null
+++ b/prep-sprint5/inheritance.py
@@ -0,0 +1,47 @@
+'''
+Play computer with this code. Predict what you expect each line will do. 
+Then run the code and check your predictions. (If any lines cause errors, 
+you may need to comment them out to check later lines).
+'''
+
+class Parent:
+    def __init__(self, first_name: str, last_name: str):
+        self.first_name = first_name
+        self.last_name = last_name
+
+    def get_name(self) -> str:
+        return f"{self.first_name} {self.last_name}"
+
+
+class Child(Parent):
+    def __init__(self, first_name: str, last_name: str):
+        super().__init__(first_name, last_name)
+        self.previous_last_names = []
+
+    def change_last_name(self, last_name) -> None:
+        self.previous_last_names.append(self.last_name)
+        self.last_name = last_name
+
+    def get_full_name(self) -> str:
+        suffix = ""
+        if len(self.previous_last_names) > 0:
+            suffix = f" (née {self.previous_last_names[0]})"
+        return f"{self.first_name} {self.last_name}{suffix}"
+
+person1 = Child("Elizaveta", "Alekseeva")
+print(person1.get_name())
+print(person1.get_full_name())
+person1.change_last_name("Tyurina")
+print(person1.get_name())
+print(person1.get_full_name())
+
+person2 = Parent("Elizaveta", "Alekseeva")
+print(person2.get_name())
+#print(person2.get_full_name())
+#person2.change_last_name("Tyurina")
+#print(person2.get_name())
+#print(person2.get_full_name())
+
+# PREDICTION:
+# Printing from person1 (Child) will work fine, as the Child class inherits from the Parent class and has access to its own methods.
+# Printing from person2 (Parent) will get error because the Parent class does not have the methods get_full_name and change_last_name defined in the Child class.
diff --git a/prep-sprint5/methods-person.py b/prep-sprint5/methods-person.py
new file mode 100644
index 00000000..7a49086e
--- /dev/null
+++ b/prep-sprint5/methods-person.py
@@ -0,0 +1,24 @@
+
+from datetime import date
+
+class Person:
+    def __init__(self, name: str, date_of_birth: date, preferred_operating_system: str):
+        self.name = name
+        self.date_of_birth = date_of_birth
+        self.preferred_operating_system = preferred_operating_system
+
+    def is_adult(self) -> bool:
+        today_year = date.today().year
+        birth_year = self.date_of_birth.year
+        age = today_year - birth_year
+
+        if date.today().month > self.date_of_birth.month:
+            return age >= 18
+        elif date.today().month == self.date_of_birth.month:
+            return date.today().day >= self.date_of_birth.day and age >= 18
+        else:
+            return age - 1 >= 18
+            
+
+imran = Person("Imran", date(2007,1,19), "Ubuntu")
+print(imran.is_adult())
\ No newline at end of file
diff --git a/prep-sprint5/mypy-checking.py b/prep-sprint5/mypy-checking.py
new file mode 100644
index 00000000..fdf82373
--- /dev/null
+++ b/prep-sprint5/mypy-checking.py
@@ -0,0 +1,30 @@
+def open_account(balances:dict, name:str, amount:int) -> None:
+    balances[name] = amount
+
+def sum_balances(accounts) -> int:
+    total = 0
+    for name, pence in accounts.items():
+        print(f"{name} had balance {pence}")
+        total += pence
+    return total
+
+def format_pence_as_string(total_pence: int) -> str:
+    if total_pence < 100:
+        return f"{total_pence}p"
+    pounds = int(total_pence / 100)
+    pence = total_pence % 100
+    return f"£{pounds}.{pence:02d}"
+
+balances = {
+    "Sima": 700,
+    "Linn": 545,
+    "Georg": 831,
+}
+
+open_account(balances,"Tobi", int(9.13 * 100))
+open_account(balances,"Olya", int(7.13 * 100))
+
+total_pence = sum_balances(balances)
+total_string = format_pence_as_string(total_pence)
+
+print(f"The bank accounts total {total_string}")
\ No newline at end of file
diff --git a/prep-sprint5/type-guided-refactoring.py b/prep-sprint5/type-guided-refactoring.py
new file mode 100644
index 00000000..1f47b6f3
--- /dev/null
+++ b/prep-sprint5/type-guided-refactoring.py
@@ -0,0 +1,52 @@
+'''Try changing the type annotation of Person.preferred_operating_system from str to List[str].
+Run mypy on the code.
+It tells us different places that our code is now wrong, because we’re passing values of the wrong type.
+We probably also want to rename our field - lists are plural. Rename the field to preferred_operating_systems.
+Run mypy again.
+Fix all of the places that mypy tells you need changing. Make sure the program works as you’d expect.'''
+
+from dataclasses import dataclass
+from typing import List
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    age: int
+    preferred_operating_systems: List[str]
+
+
+@dataclass(frozen=True)
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    screen_size_in_inches: float
+    operating_system: str
+
+
+def find_possible_laptops(laptops: List[Laptop], person: Person) -> List[Laptop]:
+    possible_laptops = []
+    for laptop in laptops:
+        if laptop.operating_system in person.preferred_operating_systems:
+            possible_laptops.append(laptop)
+    return possible_laptops
+
+
+people = [
+    Person(name="Imran", age=22, preferred_operating_systems=["Ubuntu", "Arch Linux"]),
+    Person(name="Eliza", age=34, preferred_operating_systems=["Arch Linux"]),
+]
+
+laptops = [
+    Laptop(id=1, manufacturer="Dell", model="XPS", screen_size_in_inches=13, operating_system="Arch Linux"),
+    Laptop(id=2, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system="Ubuntu"),
+    Laptop(id=3, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system="ubuntu"),
+    Laptop(id=4, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system="macOS"),
+]
+
+for person in people:
+    possible_laptops = find_possible_laptops(laptops, person)
+    print(f"Possible laptops for {person.name}: ")
+    for each in possible_laptops:
+        print(f" - ID:{each.id} {each.manufacturer} {each.model} ({each.operating_system})")
+    print()