def METHOD_NAME(img_name=None):
    """Grab an image from the standard location.
    Returns a list of standard images if called without arguments.
    Could be made more fancy to allow for more relocatability"""
    try:
        fsldir = os.environ["FSLDIR"]
    except KeyError:
        raise Exception("FSL environment variables not set")
    stdpath = os.path.join(fsldir, "data", "standard")
    if img_name is None:
        return [
            filename.replace(stdpath + "/", "")
            for filename in glob(os.path.join(stdpath, "*nii*"))
        ]
    return os.path.join(stdpath, img_name)