_getDefaultMethodDefinition(id){
    const hash = web3Utils.keccak256(id).slice(2,10);
    const method = this._getDefaultMethodIdentifier(id);

    return (this.viaIR)
      ? ``
      : `\nfunction ${method}(bytes8 c__${hash}) internal pure {}\n`;
  }
Generates an instrumentation fn definition for contract scoped methods.
Declared once per contract.
@param  {String} id
@return {String}