from pathlib import Path


def get_file_extension(filepath: str) -> str:
    """
    Returns the extension for a given filepath

    Examples:
        get_file_extension("myfile.txt") == "txt"
        get_file_extension("myfile.tar.gz") == "tar.gz"
        get_file_extension("myfile") == ""
    """
    extension_with_dot = "".join(Path(filepath).suffixes).lower()
    if extension_with_dot:
        return extension_with_dot[1:]
    return ""