def set_default_colours(**kwargs):
    """ Register a default value for a colour. Use this functionality in the source file
        where you intend to use those colours so that defaults are always available.

        Example:
            from bluesky.ui import palette
            palette.set_default_colours(mycolor1=(255, 0, 0), mycolor2=(0, 0, 0))

            This will make settings.mycolor1 and settings.mycolor2 available,
            with the provided default values."""
    for key, value in kwargs.items():
        if key not in globals():
            globals()[key] = value
