#! /usr/bin/env/python
import os
import click

def get_colors(ctx, args, incomplete):
    colors = [('red', 'a warm color'),
              ('blue', 'a cool color'),
              ('green', 'the other starter color')]
    return [c for c in colors if incomplete in c[0]]

@click.command()
@click.argument("color", type=click.STRING, autocompletion=get_colors)
def cmd1(color):
    click.echo('Chosen color is %s' % color)


if __name__ == '__main__':
    cmd1()