readTSData & write2TSData Not declared in arduino 1.8.5 sketch scope

I am attempting to follow this tutorial: https://www.mathworks.com/help/thingspeak/read-and-post-temperature-data.html, but getting errors that readTSData & WriteTSData have not been declared when uploading the sketch. Error message:

Arduino: 1.8.5 (Linux), Board: "NodeMCU 1.0 (ESP-12E Module), 80 MHz, Flash, 4M (1M SPIFFS), v2 Lower Memory, Disabled, None, Only Sketch, 115200"
/home/raymond/Arduino/sketch_apr10a/sketch_apr10a.ino: In function 'void setup()':
sketch_apr10a:38: error: 'readTSData' was not declared in this scope
aConst = readTSData( channelID, aField );
                                      ^
/home/raymond/Arduino/sketch_apr10a/sketch_apr10a.ino: In function 'void loop()':
sketch_apr10a:58: error: 'write2TSData' was not declared in this scope
       write2TSData( channelID , dataFieldOne , celsiusTemperature , dataFieldTwo , fahrenheitTemperature , dataFieldThree , millis() );      // Write the temperature in F, C, and time since starting.
                                                                                                                                      ^
exit status 1
'readTSData' was not declared in this scope

Sketch used is attached

Any help is appreciated!