Helper function to retrieve stage variables from pillars/options, if the
    input is a string

def _get_stage_variables(stage_variables):
    '''
    Helper function to retrieve stage variables from pillars/options, if the
    input is a string
    '''
    ret = dict()
    if stage_variables is None:
        return ret

    if isinstance(stage_variables, six.string_types):
        if stage_variables in __opts__:
            ret = __opts__[stage_variables]
        master_opts = __pillar__.get('master', {})
        if stage_variables in master_opts:
            ret = master_opts[stage_variables]
        if stage_variables in __pillar__:
            ret = __pillar__[stage_variables]
    elif isinstance(stage_variables, dict):
        ret = stage_variables

    if not isinstance(ret, dict):
        ret = dict()

    return ret