'Create a table of color schemes.
The table can be created empty and manually filled or it can be
created with a list of valid color schemes AND the specification for
the default active scheme.'

def __init__(self, scheme_list=None, default_scheme=''):

    self.active_scheme_name = ''
    self.active_colors = None
    if scheme_list:
        if (default_scheme == ''):
            raise ValueError('you    must    specify    the    default    color    scheme')
        for scheme in scheme_list:
            self.add_scheme(scheme)
        self.set_active_scheme(default_scheme)
