RuntimeError: Function transfer is not constant: transfer, requires to sign transaction

[noydarly]

Hi, everyone I am going to send transfer using ruby. this is my code. web3 = Web3::Eth::Rpc.new host: 'ropsten.infura.io', port: 443,
connect_options: { open_timeout: 20, read_timeout: 140, use_ssl: true, rpc_path: '/xxxxxxxxxx' } ERC_ABI = '[{.....}]' contractAddr = "0xFf............" contract = web3.eth.contract(ERC_ABI).at(contractAddr) data = contract.transfer.getData('0xg.......', 10000, {from: '0xc........'})

but i get some error. please help me. Best regards.