code: function drive(velocity, radius) {
  	if(velocity!=null) this.motorVel = velocity;
  	if(radius!=null) this.motorRad = radius;
  	this.motorL = this.motorR = this.motorLs = this.motorRs = 0;
  	this.write(137); this.write(signedInt16(this.motorVel));
  	this.write(signedInt16(this.motorRad));
  }
docs: ----------- Create 2 Motor Control -----------