code: def get_docstring(node):
      
      if not isinstance(node, (FunctionDef, ClassDef, Module)):
          raise TypeError("%r can't have docstrings" % node.__class__.__name__)
      if node.body and isinstance(node.body[0], Str):
          return node.body[0].s
docs: Return the docstring for the given node or `None` if no docstring can be
      found.  If the node provided does not accept docstrings a `TypeError`
      will be raised.