Question 2: Regular Expressions (10%) Write a regular expression pattern matching any string consisting of fields separated by commas. A field may include any printable characters except whitespaces and commas. A valid string must start and end with a field. For example, the strings 'abic,de_f , xyz' , 'abic,de-% ^ f,xyz' , abc are valid whereas the strings 'ablc,, de_f' and'ablc,de_f, xyz,' are not. In [22]: # Put your pattern inside ' , csv-regex Your solution is correct if the value returned by re.compile(csv_regex) . fullmatch(s) is not None for every string s which is valid according to the definition above, and None , otherwise