(self, key)
return self._key_at(pos)
Returns the closest key equal to or greater than the given key. If
        there is no key in the file equal to or greater than the given key,
        returns None.
Returns the closest key equal to or greater than the given key. If
        there is no key in the file equal to or greater than the given key,
        returns None.
Returns the closest key equal to or greater than the given key . If there is no key in the file equal to or greater than the given key returns None .
def closest_key(self, key):
        """Returns the closest key equal to or greater than the given key. If
        there is no key in the file equal to or greater than the given key,
        returns None.
        """

        pos = self._closest_key_pos(key)
        if pos is None:
            return None
        return self._key_at(pos)
def closest_key ( self , key ) : pos = self . _closest_key_pos ( key ) if pos is None : return None return self . _key_at ( pos )