code: def get_module_functions(modules):
    
    module_fns = set()
    for module in modules:
      for key in dir(module):
        attr = getattr(module, key)
        if isinstance(
            attr, (types.BuiltinFunctionType, types.FunctionType, numpy.ufunc)):
          module_fns.add(attr)
    return module_fns
docs: Finds functions that do not have implemented derivatives.
  
    Args:
      modules: A list of Python modules. Functions contained in these modules
          will be checked for membership in 'implemented', and if not found,
          will be added to an 'unimplemented' set
      implemented: A Python object containing implemented derivatives. A function
          should be checkable for membership using the `fn in implemented` syntax.
  
    Returns:
      module_fns: A set of functions, builtins or ufuncs in `modules`.