@staticmethod
def map_list(lst, field_name):
    """
        Create hashtable from list

        map_list([{a: 1, b: 2}, {a: 3, b: 4}], 'a') => {1: {a: 1, b:2}, 3: {a: 3, b: 4}}
        """
    ret = {}
    for item in lst:
        if field_name in item:
            ret[item[field_name]] = item
    return ret
