Fill the value of the regex variable with a regular expression. It should match the "python" substring (without quotes) when it is located at the very beginning of some alphanumeric sequence. In other words, it should be a part of a bigger word.
For example, your regular expression should match the strings "python3", "pythonist", "pythonnn" (without quotes), but not the strings "python", "what is python?", "python is worse than java" (without quotes).
Tip: What metacharacter matches the word boundary absence?
