Remove unused "pip._internal.utils.misc.cached_property"

src/pip/_internal/utils/misc.py

@@ -603,26 +603,6 @@ def captured_stderr():
     return captured_output('stderr')
 
 
-class cached_property(object):
-    """A property that is only computed once per instance and then replaces
-       itself with an ordinary attribute. Deleting the attribute resets the
-       property.
-
-       Source: https://github.com/bottlepy/bottle/blob/0.11.5/bottle.py#L175
-    """
-
-    def __init__(self, func):
-        self.__doc__ = getattr(func, '__doc__')
-        self.func = func
-
-    def __get__(self, obj, cls):
-        if obj is None:
-            # We're being accessed from the class itself, not from an object
-            return self
-        value = obj.__dict__[self.func.__name__] = self.func(obj)
-        return value
-
-
 def get_installed_version(dist_name, working_set=None):
     """Get the installed version of dist_name avoiding pkg_resources cache"""
     # Create a requirement that we'll look for inside of setuptools.