human
I wrote the below code

    def call_and_assert(arg, context=None):
        if (context is None):
            context = {}
        result = function(arg, context=context)
        assert (result == arg), 'Should    return    the    argument    that    was    passed    to    it,    unchanged    ({arg})'.format(arg=repr(arg))
        return result
    return call_and_assert

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def returns_arg(function):