<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_node(self, key):
 """Delegate to our current "value provider" for the node belonging to this key."""

    if key in self.names:
      return self.values.get_member_node(key) if hasattr(self.values, 'get_member_node') else None
    return self.parent.get_node(key)