mmcv/utils/misc.py
def check_prerequisites(
        prerequisites,
        checker,
        msg_tmpl='Prerequisites "{}" are required in method "{}" but not '
        'found, please install them first.'):
    """A decorator factory to check if prerequisites are satisfied.

    Args:
        prerequisites (str of list[str]): Prerequisites to be checked.
        checker (callable): The checker method that returns True if a
            prerequisite is meet, False otherwise.
        msg_tmpl (str): The message template with two variables.

    Returns:
        decorator: A specific decorator.
    """

    def wrap(func):

        @functools.wraps(func)
        def wrapped_func(*args, **kwargs):
            requirements = [prerequisites] if isinstance(
                prerequisites, str) else prerequisites
            missing = []
            for item in requirements:
                if not checker(item):
                    missing.append(item)
            if missing:
                print(msg_tmpl.format(', '.join(missing), func.__name__))
                raise RuntimeError('Prerequisites not meet.')
            else:
                return func(*args, **kwargs)

        return wrapped_func

    return wrap
def check_prerequisites(
        prerequisites,
        checker,
        msg_tmpl='Prerequisites "{}" are required in method "{}" but not '
        'found, please install them first.'):
    def wrap(func):

        @functools.wraps(func)
        def wrapped_func(*args, **kwargs):
            requirements = [prerequisites] if isinstance(
                prerequisites, str) else prerequisites
            missing = []
            for item in requirements:
                if not checker(item):
                    missing.append(item)
            if missing:
                print(msg_tmpl.format(', '.join(missing), func.__name__))
                raise RuntimeError('Prerequisites not meet.')
            else:
                return func(*args, **kwargs)

        return wrapped_func

    return wrap
def check_prerequisites ( prerequisites , checker , msg_tmpl = 'Prerequisites "{}" are required in method "{}" but not ' 'found, please install them first.' ) : def wrap ( func ) : @ functools . wraps ( func ) def wrapped_func ( * args , * * kwargs ) : requirements = [ prerequisites ] if isinstance ( prerequisites , str ) else prerequisites missing = [ ] for item in requirements : if not checker ( item ) : missing . append ( item ) if missing : print ( msg_tmpl . format ( ', ' . join ( missing ) , func . __name__ ) ) raise RuntimeError ( 'Prerequisites not meet.' ) else : return func ( * args , * * kwargs ) return wrapped_func return wrap
A decorator factory to check if prerequisites are satisfied.

    Args:
        prerequisites (str of list[str]): Prerequisites to be checked.
        checker (callable): The checker method that returns True if a
            prerequisite is meet, False otherwise.
        msg_tmpl (str): The message template with two variables.

    Returns:
        decorator: A specific decorator.
A decorator factory to check if prerequisites are satisfied .