options.py 文件源码

def has_module(name):
    """
    Check if the Python module 'name' is available.

    Parameters
    ----------
    name : str
        The name of the Python module, as used in an import instruction.

    This function uses ideas from this Stack Overflow question:
    http://stackoverflow.com/questions/14050281/

    Returns
    -------
    b : bool
        True if the module exists, or False otherwise.
    """

    if sys.version_info > (3, 3):
        import importlib.util
        return importlib.util.find_spec(name) is not None
    elif sys.version_info > (2, 7, 99):
        import importlib
        return importlib.find_loader(name) is not None
    else:
        import pkgutil
        return pkgutil.find_loader(name) is not None