How to use the chartpress.image_needs_building function in chartpress

def _capture_output(args, capfd):
    """
    Calls chartpress given provided arguments and captures the output during the
    call.
    """
    # clear cache of in memory cached functions
    # this allows us to better mimic the chartpress CLI behavior
    chartpress.image_needs_building.cache_clear()
    chartpress.image_needs_pushing.cache_clear()
    chartpress.latest_tag_or_mod_commit.cache_clear()

    # first flush past captured output, then run chartpress, and finally read
    # and save all output that came of it
    _, _ = capfd.readouterr()
    chartpress.main(args)
    out, err = capfd.readouterr()

    # since the output was captured, print it back out again for debugging
    # purposes if a test fails for example
    header = f'--- chartpress {" ".join(args)} ---'
    footer = "-" * len(header)
    print()
    print(header)
    print(out)