<human>:  regexpression not match comment.
<bot>: Here is a Python function for regexpression not matching the comment

import re

def _regex_not_match_comment(s):
  """
  Check if regex expression not match comment.
  """
  return re.search(r'^\s*#', s) is None

# Enter the string
string = "This is a comment"

# Calling the function
print((_regex_not_match_comment(string)))

#Example Output
# True

#Remember to inspect code for bugs.