code: def add_book(self, publisher=None, place=None, date=None):
          
  
          imprint = {}
          if date is not None:
              imprint['date'] = normalize_date(date)
          if place is not None:
              imprint['place'] = place
          if publisher is not None:
              imprint['publisher'] = publisher
  
          self._append_to('imprints', imprint)
docs: Make a dictionary that is representing a book.
  
          :param publisher: publisher name
  
          :type publisher: string
  
          :param place: place of publication
          :type place: string
  
          :param date: A (partial) date in any format.
              The date should contain at least a year
          :type date: string
  
          :rtype: dict