diff --git a/func_py/func.py b/func_py/func.py
index 05e6607..653c6a9 100644
--- a/func_py/func.py
+++ b/func_py/func.py
@@ -40,7 +40,7 @@ class function:
 
         sig_g = signature(g)
         g_req_params = [v for k, v in sig_g.parameters.items() if v.default == _empty]
-        g_typed_req_params = [p if p.annotation == _empty else Parameter(name=p.name, annotation=Any, kind=Parameter.POSITIONAL_ONLY) for p in g_req_params]
+        g_typed_req_params = [p if p.annotation == _empty else Parameter(name=p.name, annotation=Any, kind=Parameter.POSITIONAL_OR_KEYWORD) for p in g_req_params]
 
         def h(*args, **kwargs):
             return f(g(*args, **kwargs))
@@ -49,18 +49,33 @@ class function:
         h.__signature__ = sig_g.replace(parameters=g_typed_req_params, return_annotation=Any if f_ret_type == _empty else f_ret_type)
         return function(h)
 
+    #TODO: complexity prop
+
+    #TODO: getter for inverse function
 
     #TODO: implement fly weight pattern
 
     def __init__(self, f):
         self.original_func = f
         self.signature = signature(f) #TODO: change to support pattern matching: sig ((int, str), {"name": str})
-        self.__signature__ = signature(f)
+
+        sig = signature(f)
+        req_params = {k: v for k, v in sig.parameters.items() if v.default == _empty}
+        params = []
+        for name, p in req_params.items():
+            if p.annotation == _empty:
+                params.append( Parameter(name=name, annotation=Any, kind=Parameter.POSITIONAL_OR_KEYWORD) )
+            else:
+                params.append(p)
+
+        self.__signature__ = sig.replace(parameters=params, return_annotation=Any if sig.return_annotation == _empty else sig.return_annotation)
+
+
         self.cache = {}
         self.is_pure = True
 
     def __str__(self):
-        return str(signature(self.original_func)).replace(", /)", ")")
+        return str(self.__signature__)
 
     def __repr__(self):
         return str(self)
@@ -77,14 +92,17 @@ class function:
 
     @property
     def required_args(self):
-        return [(k, v) for k, v in signature(self.original_func).parameters.items() if v.default == _empty]
+        return [(name, param) for name, param in self.__signature__.parameters.items() if param.default == _empty]
+
 
     def __call__(self, *args, **kwargs):
-        if len(args) < len(self.required_args):
-            sig = signature(self.original_func)
-            f = partial(self.original_func, *args)
-            req_params = [v for k, v in sig.parameters.items() if v.default == _empty]
-            remaining_params = req_params[len(args):]
+        provided_req_kwargs = {k for k, p in self.required_args if k in kwargs}
+        num_given_req_args = len(args) + len(provided_req_kwargs)
+
+        if num_given_req_args < len(self.required_args):
+            sig = self.__signature__
+            f = partial(self.original_func, *args, **kwargs)
+            remaining_params = [v for k, v in sig.parameters.items() if v.default == _empty and k not in provided_req_kwargs][len(args):]
             f.__signature__ = sig.replace(parameters=remaining_params, return_annotation=Any if sig.return_annotation == _empty else sig.return_annotation)
             return function(f)