Merge pull request #6932 from takluyver/help-signatures

Better support for wrapped function signatures in help

IPython/core/oinspect.py

@@ -40,6 +40,7 b' from IPython.utils.text import indent'
 from IPython.utils.wildcard import list_namespace
 from IPython.utils.coloransi import TermColors, ColorScheme, ColorSchemeTable
 from IPython.utils.py3compat import cast_unicode, string_types, PY3
+from IPython.utils.signatures import signature
 
 # builtin docstrings to ignore
 _func_call_docstring = types.FunctionType.__call__.__doc__
@@ -390,7 +391,7 b' class Inspector:'
         If any exception is generated, None is returned instead and the
         exception is suppressed."""
         try:
-            hdef = oname + inspect.formatargspec(*getargspec(obj))
+            hdef = oname + str(signature(obj))
             return cast_unicode(hdef)
         except:
             return None

IPython/utils/signatures.py

@@ -72,8 +72,11 b' def signature(obj):'
         raise TypeError('{0!r} is not a callable object'.format(obj))
 
     if isinstance(obj, types.MethodType):
-        # In this case we skip the first parameter of the underlying
-        # function (usually `self` or `cls`).
+        if obj.__self__ is None:
+            # Unbound method - treat it as a function (no distinction in Py 3)
+            obj = obj.__func__
+        else:
+            # Bound method: trim off the first parameter (typically self or cls)
         sig = signature(obj.__func__)
         return sig.replace(parameters=tuple(sig.parameters.values())[1:])