code: def _restriction_string(self):
          
  
          if self.has_minimum:
              string = 'at least '
              value = self._minimum
          elif self.has_maximum:
              string = 'at most '
              value = self._maximum
          elif self.has_exact:
              string = ''
              value = self._exact
  
          return (string + '{} {}').format(
              value,
              pluralize('time', value)
          )
docs: Get a string explaining the expectation currently set
  
          e.g `at least 5 times`, `at most 1 time`, or `2 times`
  
          :rtype string