If you try to call EthClient.Contract.get_functions/1 with a contract address as parameter, the function will automatically try to search the functions from etherscan and will generate an error if the contract was deployed in the local node.
Error:

** (MatchError) no match of right hand side value: {:error, :unknown_chain_id_for_etherscan}
    (eth_client 0.1.0) lib/eth_client/abi.ex:12: EthClient.ABI.get_etherscan/1
    (eth_client 0.1.0) lib/eth_client/contract.ex:10: EthClient.Contract.get_functions/1

The functions works locally only if the parameter is the path to the ABI file.