@alias.command()<EOL>@click.argument('<STR_LIT>', required=True)<EOL>@click.argument('<STR_LIT>', required=True)<EOL>@click.option('<STR_LIT>', '<STR_LIT>', help="<STR_LIT>")<EOL>@click.pass_context<EOL>def add(ctx, alias, mapping, backend):
if not backend:<EOL><INDENT>backends_list = ctx.obj['<STR_LIT>'].get_backends()<EOL>if len(backends_list) > <NUM_LIT:1>:<EOL><INDENT>raise click.UsageError(<EOL>"<STR_LIT>"<EOL>"<STR_LIT>" %<EOL>"<STR_LIT:U+002CU+0020>".join(dict(backends_list).keys())<EOL>)<EOL><DEDENT><DEDENT>add_mapping(ctx, alias, mapping, backend)<EOL>
Add a new alias to your configuration file.