def _get_params(self, p_dict):
    key = p_dict['key']
    if ('var' in p_dict.keys()):
        var = p_dict['var']
    else:
        var = self.var
    if ('agg' in p_dict.keys()):
        agg = p_dict['agg']
    else:
        agg = self.agg
    if ('on' in p_dict.keys()):
        on = p_dict['on']
    else:
        on = key
    return (key, var, agg, on)
def _get_params(self, p_dict):
    key = p_dict['key']
    if ('var' in p_dict.keys()):
        var = p_dict['var']
    else:
        var = self.var
    if ('agg' in p_dict.keys()):
        agg = p_dict['agg']
    else:
        agg = self.agg
    if ('on' in p_dict.keys()):
        on = p_dict['on']
    else:
        on = key
    return (key, var, agg, on)