human
I wrote the below code

    def getter(self):
        return self.environ.get(environ_field, None)
    def setter(self, value):
        if isinstance(value, six.text_type):
            self.environ[environ_field] = value.encode('utf-8')
        else:
            self.environ[environ_field] = value
    return property(getter, setter, doc=('Get    and    set    the    %s    property    in    the    WSGI    environment' % environ_field))

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

def _req_environ_property(environ_field):