code: function areEquivalentValues(command, val1, val2) {
  	if (val1 === null && val2 === null) {
  		return true;
  	}
  
  	if (typeof val1 == "string"
  	&& typeof val2 == "string"
  	&& val1 == val2
  	&& !("equivalentValues" in commands[command])) {
  		return true;
  	}
  
  	if (typeof val1 == "string"
  	&& typeof val2 == "string"
  	&& "equivalentValues" in commands[command]
  	&& commands[command].equivalentValues(val1, val2)) {
  		return true;
  	}
  
  	return false;
  }
docs: "Two quantities are equivalent values for a command if either both are null, or both are strings and they're equal and the command does not define any equivalent values, or both are strings and the command defines equivalent values and they match the definition."