code: def icons(self, left=None):
          
          if left is not None:
              return self._icons[left]
          else:
              return list(chain.from_iterable(self._icons.values()))
docs: Return the ICONS with left variable *left*, or all ICONS.
  
          Args:
              left: the left variable of the ICONS to return; if `None`,
                  return all ICONS