Returns or sets (if a value is provided) the diameter of the series'
        data points.

        :param Number size: If given, the series' size will be set to\
        this.
        :rtype: ``Number``

def size(self, size=None):
        """Returns or sets (if a value is provided) the diameter of the series'
        data points.

        :param Number size: If given, the series' size will be set to\
        this.
        :rtype: ``Number``"""

        if size is None:
            return self._size
        else:
            if not is_numeric(size):
                raise TypeError(
                 "size must be number, not '%s'" % str(size)
                )
            self._size = size