def size(self, size=None):
if size is None:<EOL><INDENT>return self._size<EOL><DEDENT>else:<EOL><INDENT>if not is_numeric(size):<EOL><INDENT>raise TypeError(<EOL>"<STR_LIT>" % str(size)<EOL>)<EOL><DEDENT>self._size = size<EOL><DEDENT>
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``