def collect_usage_pieces(self, ctx):
        """Returns all the pieces that go into the usage line and returns
        it as a list of strings.
        """
        rv = [self.options_metavar]
        for param in self.get_params(ctx):
            rv.extend(param.get_usage_pieces(ctx))
        return rv
Returns all the pieces that go into the usage line and returns
        it as a list of strings.
        
dynaconf/vendor/click/core.py