Fix deprecation warnings due to invalid escape sequences.

callee/base.py

@@ -147,7 +147,7 @@ class Matcher(BaseMatcher):
     for better error messages.
     """
     def __repr__(self):
-        """Provides a default ``repr``\ esentation for custom matchers.
+        r"""Provides a default ``repr``\ esentation for custom matchers.
 
         This representation will include matcher class name
         and the values of its public attributes.

callee/collections.py

@@ -95,7 +95,7 @@ def __init__(self):
 
 
 class Generator(BaseMatcher):
-    """Matches an iterable that's a generator.
+    r"""Matches an iterable that's a generator.
 
     A generator can be a generator expression ("comprehension")
     or an invocation of a generator function (one that ``yield``\ s objects).

callee/numbers.py

@@ -43,7 +43,7 @@ class Number(NumericMatcher):
 
 
 class Complex(NumericMatcher):
-    """Matches any complex number.
+    r"""Matches any complex number.
 
     This *includes* all real, rational, and integer numbers as well,
     which in Python translates to `float`\ s, fractions, and `int`\ egers.
@@ -57,7 +57,7 @@ class Complex(NumericMatcher):
 
 
 class Real(NumericMatcher):
-    """Matches any real number.
+    r"""Matches any real number.
 
     This includes all rational and integer numbers as well, which in Python
     translates to fractions, and `int`\ egers.
@@ -72,7 +72,7 @@ class Float(NumericMatcher):
 
 
 class Rational(NumericMatcher):
-    """Matches a rational number.
+    r"""Matches a rational number.
     This includes all `int`\ eger numbers as well.
     """
     CLASS = numbers.Rational

callee/operators.py

@@ -185,7 +185,7 @@ class Shorter(LengthMatcher):
 
 
 class ShorterOrEqual(LengthMatcher):
-    """Matches values that are shorter than,
+    r"""Matches values that are shorter than,
     or equal in ``len``\ gth to (as per ``<=`` operator), given object.
     """
     OP = operator.le
@@ -203,7 +203,7 @@ class Longer(LengthMatcher):
 
 
 class LongerOrEqual(LengthMatcher):
-    """Matches values that are longer than,
+    r"""Matches values that are longer than,
     or equal in ``len``\ gth to (as per ``>=`` operator), given object.
     """
     OP = operator.ge

callee/types.py

@@ -16,7 +16,7 @@ class TypeMatcher(BaseMatcher):
     This class shouldn't be used directly.
     """
     def __init__(self, type_):
-        """:param type\ _: Type to match against"""
+        r""":param type\ _: Type to match against"""
         if not isinstance(type_, type):
             raise TypeError("%s requires a type, got %r" % (
                 self.__class__.__name__, type_))
@@ -32,7 +32,7 @@ class InstanceOf(TypeMatcher):
     (as per `isinstance`).
     """
     def __init__(self, type_, exact=False):
-        """
+        r"""
         :param type\ _: Type to match against
         :param exact:
 
@@ -58,7 +58,7 @@ class SubclassOf(TypeMatcher):
     (as per `issubclass`).
     """
     def __init__(self, type_, strict=False):
-        """
+        r"""
         :param type\ _: Type to match against
         :param strict: