    def __init__(self, screen, x, y, life_time, diameter=None, **kwargs):
        """
        See :py:obj:`.ParticleEffect` for details of the parameters.

        In addition, it is possible to set the diameter of this effect using the extra keyword parameter.
        """
        # Need to set the field first because the underlying constructor calls reset.
        self._diameter = diameter
        super().__init__(screen, x, y, life_time, **kwargs)
See :py:obj:`.ParticleEffect` for details of the parameters.

In addition, it is possible to set the diameter of this effect using the extra keyword parameter.
asciimatics/particles.py