Add materials for exceptions update (#493)

* Add materials for exceptions update

* Fix linter flag

* Final QA

---------

Co-authored-by: KateFinegan <[email protected]>
Co-authored-by: gahjelle <[email protected]>

Author: 3 people

python-exceptions/README.md

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+# Python Exceptions: An Introduction
+
+This folder provides the code examples for the Real Python tutorial [Python Exceptions: An Introduction](https://realpython.com/python-exceptions/).

python-exceptions/linux_interaction.py

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+class PlatformException(Exception):
+    """Incompatible platform."""
+
+
+def linux_interaction():
+    import sys
+
+    if "linux" not in sys.platform:
+        raise PlatformException("Function can only run on Linux systems.")
+    print("Doing Linux things.")
+
+
+try:
+    linux_interaction()
+except PlatformException as error:
+    print(error)
+    print("The linux_interaction() function wasn't executed.")

python-exceptions/low.py

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+number = 10
+assert number < 5, f"The number should not exceed 5. ({number=})"
+print(number)

python-exceptions/open_file.py

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+try:
+    with open("file.log") as file:
+        read_data = file.read()
+except FileNotFoundError as fnf_error:
+    print(fnf_error)

python-exceptions/try_except_else_finally.py

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+def linux_interaction():
+    import sys
+
+    if "linux" not in sys.platform:
+        raise RuntimeError("Function can only run on Linux systems.")
+    print("Doing Linux things.")
+
+
+try:
+    linux_interaction()
+except RuntimeError as error:
+    print(error)
+else:
+    try:
+        with open("file.log") as file:
+            read_data = file.read()
+    except FileNotFoundError as fnf_error:
+        print(fnf_error)
+finally:
+    print("Cleaning up, irrespective of any exceptions.")