def remove_subkey(self, subkey):
        """
        Remove the given subkey, if existed, from this AdfKey.

        Parameters
        ----------
        subkey : str or AdfKey
            The subkey to remove.

        """
        if len(self.subkeys) > 0:
            key = subkey if isinstance(subkey, str) else subkey.key
            for i in range(len(self.subkeys)):
                if self.subkeys[i].key == key:
                    self.subkeys.pop(i)
                    break