docs: def popleft(self, block=True, timeout=None):
          """Remove and return an item from the right side of the
          GeventDeque. If no elements are present, raises an IndexError.
  
          If optional args *block* is True and *timeout* is ``None``
          (the default), block if necessary until an item is
          available. If *timeout* is a positive number, it blocks at
          most *timeout* seconds and raises the :class:`IndexError`
          exception if no item was available within that time. Otherwise
          (*block* is False), return an item if one is immediately
          available, else raise the :class:`IndexError` exception
          (*timeout* is ignored in that case).
          """
          return self._pop(block, timeout, left=True)