docs: def set_default_formatters(self, which=None):
          """Sets the default formatters that is used for updating to None
  
          Parameters
          ----------
          which: {None, 'minor', 'major'}
              Specify which locator shall be set"""
          if which is None or which == 'minor':
              self.default_formatters['minor'] = self.axis.get_minor_formatter()
          if which is None or which == 'major':
              self.default_formatters['major'] = self.axis.get_major_formatter()