'Set properties for the chart drop lines.
Args:
options: A dictionary of options.
Returns:
Nothing.'

def set_drop_lines(self, options=None):

    if (options is None):
        options = {}
    line = Shape._get_line_properties(options.get('line'))
    fill = Shape._get_fill_properties(options.get('fill'))
    pattern = Shape._get_pattern_properties(options.get('pattern'))
    gradient = Shape._get_gradient_properties(options.get('gradient'))
    if pattern:
        self.fill = None
    if gradient:
        pattern = None
        fill = None
    self.drop_lines = {'line': line, 'fill': fill, 'pattern': pattern, 'gradient': gradient}
