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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 check_set(set=None, family='ipv4'):
    '''
    Check that given ipset set exists.

    .. versionadded:: 2014.7.0

    CLI Example:

    .. code-block:: bash

        salt '*' ipset.check_set setname

    '''
    if not set:
        return 'Error: Set needs to be specified'

    setinfo = _find_set_info(set)
    if not setinfo:
        return False
    return True