rule foo:
    """
    Do foo
    
    :output: - foo file for ``{par}``

    """
    output: "foo_{par}.test"
    shell:
        """
        touch {output}
        """
        
rule bar:
    """
    Do foo
    
    :output: - ``bar`` file

    :input: - ``foo`` file

    """
    output:
        bar = "bar_{par}.test"
    input:
        foo = "foo_{par}.test"

def test_func(wildcards):
    """
    I'm a test function
    """
    return wildcards
