diff --git a/kani/utils/deprecation.py b/kani/utils/deprecation.py
deleted file mode 100644
index 991ff28..0000000
--- a/kani/utils/deprecation.py
+++ /dev/null
@@ -1,73 +0,0 @@
-import functools
-import inspect
-import warnings
-
-string_types = (type(b""), type(""))
-
-
-# deprecated wrapper from https://stackoverflow.com/a/40301488
-def deprecated(reason):
-    """
-    This is a decorator which can be used to mark functions
-    as deprecated. It will result in a warning being emitted
-    when the function is used.
-    """
-
-    if isinstance(reason, string_types):
-
-        # The @deprecated is used with a 'reason'.
-        #
-        # .. code-block:: python
-        #
-        #    @deprecated("please, use another function")
-        #    def old_function(x, y):
-        #      pass
-
-        def decorator(func1):
-
-            if inspect.isclass(func1):
-                fmt1 = "Call to deprecated class {name} ({reason})."
-            else:
-                fmt1 = "Call to deprecated function {name} ({reason})."
-
-            @functools.wraps(func1)
-            def new_func1(*args, **kwargs):
-                warnings.simplefilter("always", DeprecationWarning)
-                warnings.warn(
-                    fmt1.format(name=func1.__name__, reason=reason), category=DeprecationWarning, stacklevel=2
-                )
-                warnings.simplefilter("default", DeprecationWarning)
-                return func1(*args, **kwargs)
-
-            return new_func1
-
-        return decorator
-
-    elif inspect.isclass(reason) or inspect.isfunction(reason):
-
-        # The @deprecated is used without any 'reason'.
-        #
-        # .. code-block:: python
-        #
-        #    @deprecated
-        #    def old_function(x, y):
-        #      pass
-
-        func2 = reason
-
-        if inspect.isclass(func2):
-            fmt2 = "Call to deprecated class {name}."
-        else:
-            fmt2 = "Call to deprecated function {name}."
-
-        @functools.wraps(func2)
-        def new_func2(*args, **kwargs):
-            warnings.simplefilter("always", DeprecationWarning)
-            warnings.warn(fmt2.format(name=func2.__name__), category=DeprecationWarning, stacklevel=2)
-            warnings.simplefilter("default", DeprecationWarning)
-            return func2(*args, **kwargs)
-
-        return new_func2
-
-    else:
-        raise TypeError(repr(type(reason)))