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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 list_returner_functions(*args, **kwargs):  # pylint: disable=unused-argument
    '''
    List the functions for all returner modules. Optionally, specify a returner
    module or modules from which to list.

    .. versionadded:: 2014.7.0

    CLI Example:

    .. code-block:: bash

        salt '*' sys.list_returner_functions
        salt '*' sys.list_returner_functions mysql
        salt '*' sys.list_returner_functions mysql etcd

    Returner names can be specified as globs.

    .. versionadded:: 2015.5.0

    .. code-block:: bash

        salt '*' sys.list_returner_functions 'sqlite3.get_*'

    '''
    # NOTE: **kwargs is used here to prevent a traceback when garbage
    #       arguments are tacked on to the end.

    returners_ = salt.loader.returners(__opts__, [])
    if not args:
        # We're being asked for all functions
        return sorted(returners_)

    names = set()
    for module in args:
        if '*' in module or '.' in module:
            for func in fnmatch.filter(returners_, module):
                names.add(func)
        else:
            # "sys" should just match sys without also matching sysctl
            moduledot = module + '.'
            for func in returners_:
                if func.startswith(moduledot):
                    names.add(func)
    return sorted(names)