<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def remove_override(self, key):
 """Remove a setting override, if one exists."""

        keys = key.split('.')
        if len(keys) > 1:
            raise NotImplementedError
        elif key in self.overrides:
            del self.overrides[key]
            self._uncache(key)