<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def isargument(self, node):
 """ checks whether node aliases to a parameter."""

        try:
            node_id, _ = self.node_to_id(node)
            return (node_id in self.name_to_nodes and
                    any([isinstance(n, ast.Name) and
                         isinstance(n.ctx, ast.Param)
                         for n in self.name_to_nodes[node_id]]))
        except UnboundableRValue:
            return False