code: def remove_tag(self, p_key, p_value=""):
          
          self._remove_tag_helper(p_key, p_value)
  
          # when value == "", match any value having key p_key
          value = p_value if p_value != "" else r'\S+'
          self.src = re.sub(r'\s?\b' + p_key + ':' + value + r'\b', '', self.src)
docs: Removes a tag from the todo.
          When the value is empty (default), all occurrences of the tag will be
          removed.
          Else, only those tags with the value will be removed.