import re


def parse_colors(colors_string):
    """
    Return a list of colors in the format '#XXXXXX' from colors_string or
    the default colors if no color is found.
    """

    # RGB colors
    default_colors = ['#ff0000', '#00ff00', '#0000ff']
    colors = []

    if isinstance(colors_string, str):
        colors = re.findall('#[0-9a-fA-F]{6}', colors_string)

    try:
        assert colors != []
    except AssertionError:
        colors = default_colors

    return colors