# external imports
from eth_erc20 import ERC20
from chainlib.eth.constant import ZERO_ADDRESS


def token_balance(chain_spec, conn, token_address, wallet_address, caller_address=ZERO_ADDRESS):
    c = ERC20(chain_spec)
    o = c.balance(token_address, wallet_address, sender_address=caller_address)
    r = conn.do(o)
    return c.parse_balance(r)