def mutate(self):
        '''
        Mutate the field

        :rtype: boolean
        :return: True if field the mutated
        '''
        self._initialize()
        if self._exhausted():
            return False
        self._current_index += 1
        self._mutate()
        return True
Mutate the field

        :rtype: boolean
        :return: True if field the mutated