code: def delete_field(self, field_name):
      
      self._whoosh.remove_field(field_name.strip())
      return self._whoosh.schema
docs: This function deletes one determined field using the command MODEL.pw.delete_field(FIELD)
  
      Args:
          field_name (string): This argument let you delete some field for some model registered in the index.
  
      Returns:
          (WhooshSchema): The new schema after deleted is returned.