text: from mif_object import MifObject
  
  
  class Pages(MifObject):
      """
      Class to store information about the pages of a reference.
      
      The following fields must be defined:
          start
      """
      
      def __init__(self, start=None, end=None, **kwargs):
          """
          Constructor.
          
          :param start: Starting page.
          :type start: String or number.
  
          :param end: Ending page.
          :type end: String or number.
          """
          super(Pages, self).__init__(**kwargs)
          self.start = start
          self.end = end
  