Multisig.sol interface function definitions caused Remix compiler error when inherited. (medium severity)

[Dexaran]

Severity: medium

Code snippet

https://github.com/EthereumCommonwealth/ethereum-classic-multisig/blob/master/contracts/ownership/Multisig.sol#L25-L27

Description

It does not matter whether an empty function is defined as function func() external; or function func() external { }. In case of function func() external; definition Remix is unable to return the contract's bytecode.

It is highly advised to use function func() { } for empty function definitions.

Recommendation

contract Multisig {
  function changeOwner(address _from, address _to) external { }
  function execute(address _to, uint256 _value, bytes _data) external returns (bytes32) { }
  function confirm(bytes32 _h) public returns (bool) { }
}