whole_func_string: function getHead (next) {
      vm.blockchain.getHead(function (err, block) {
        // make sure the state is set before checking post conditions
        state.root = block.header.stateRoot
        next(err)
      })
    }
func_code_string: function getHead (next) {
      vm.blockchain.getHead(function (err, block) {
        // make sure the state is set before checking post conditions
        state.root = block.header.stateRoot
        next(err)
      })
    }
func_documentation_string: get the blockchain head