python类which()的实例源码

def new(cls, filename):
        if hasattr(settings, 'LEDGER_BIN'):
            ledger_bin = settings.LEDGER_BIN
        else:
            ledger_bin = sh.which('ledger')

        return Ledger(sh.Command(ledger_bin).bake(_tty_out=False, no_color=True, file=filename), filename=filename)

def get_executable_path(executable):
    path = sh.which(executable)
    if path is None:
        raise Exception("Can't find '{}' executable, is it in your $PATH?".format(executable))
    return str(path)