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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def call(conn=None, call=None, kwargs=None):
    '''
    Call function from shade.

    func

        function to call from shade.openstackcloud library

    CLI Example

    .. code-block:: bash

        salt-cloud -f call myopenstack func=list_images
        t sujksalt-cloud -f call myopenstack func=create_network name=mysubnet
    '''
    if call == 'action':
        raise SaltCloudSystemExit(
            'The call function must be called with '
            '-f or --function.'
        )

    if 'func' not in kwargs:
        raise SaltCloudSystemExit(
            'No `func` argument passed'
        )

    if conn is None:
        conn = get_conn()

    func = kwargs.pop('func')
    for key, value in kwargs.items():
        try:
            kwargs[key] = __utils__['json.loads'](value)
        except ValueError:
            continue
    try:
        return getattr(conn, func)(**kwargs)
    except shade.exc.OpenStackCloudException as exc:
        log.error('Error running %s: %s', func, exc)
        raise SaltCloudSystemExit(six.text_type(exc))