code: def _callable_contents(obj):
      
      try:
          # Test if obj is a method.
          return _function_contents(obj.__func__)
  
      except AttributeError:
          try:
              # Test if obj is a callable object.
              return _function_contents(obj.__call__.__func__)
  
          except AttributeError:
              try:
                  # Test if obj is a code object.
                  return _code_contents(obj)
  
              except AttributeError:
                  # Test if obj is a function object.
                  return _function_contents(obj)
docs: Return the signature contents of a callable Python object.