def get_env_variable(key, default=None):
    """Get an environment variable from the system."""
    result = None
    try:
        result = os.environ[key]
    except KeyError:
        if default is not None:
            result = default
        else:
            msg = (key) % "Set the {} environment variable"
            raise ImproperlyConfigured(msg)
    return booleanize_if_possible(result)

# Read each line in the manifest.
dataset/ETHPy150Open 0xadada/dockdj/app/project/settings.py/get_env_variable/swapped operands of `%`