import json


def readAddressStruct(filename):
    """
    read addrStruct from json formated file filename
    function assumes path directory structure exists and will error if not
    
    Args:
        filename (str): string path to read from
    Returns:
        None or dictionary addrStruct
        addrStruct (dict): dictionary of url keys with list of list values
            created by buildAddressStruct
    """
    addrStruct = None
    with open(filename, 'r') as fJson:
        addrStruct = json.load(fJson)
    return(addrStruct)