code: def get_tag_hash(self, tag_name):
          
          tag_object = get_single_item_from_sequence(
              sequence=self._github_repository.tags(),
              condition=lambda tag: tag.name == tag_name,
              no_item_error_message='No tag "{}" exist'.format(tag_name),
              too_many_item_error_message='Too many tags "{}" found'.format(tag_name),
          )
  
          return tag_object.commit.sha
docs: Fetch the commit hash that was tagged with ``tag_name``.
  
          Args:
              tag_name (str): the name of the tag
  
          Returns:
              str: the commit hash linked by the tag