def is_inverted(photo_interp: str) -> bool:
    """Checks if pixel value 0 corresponds to white. See DICOM specification for more details."""
    if photo_interp == "MONOCHROME1":
        return True
    elif photo_interp != "MONOCHROME2":
        # I don't think we need to handle any interpretations besides MONOCHROME1
        # and MONOCHROME2 in the case of mammograms.
        raise Exception(f"Unexpected photometric interpretation '{photo_interp}'")
    return False