How to check if a string is a valid regex in Python?

In Java, I could use the following function to check if a string is a valid regex (source):

boolean isRegex;
try {
  Pattern.compile(input);
  isRegex = true;
} catch (PatternSyntaxException e) {
  isRegex = false;
}

Is there a Python equivalent of the Pattern.compile() and PatternSyntaxException? If so, what is it?

Answer

Similar to Java. Use re.error exception:

import re

try:
    re.compile('[')
    is_valid = True
except re.error:
    is_valid = False

exception re.error

Exception raised when a string passed to one of the functions here is not a valid regular expression (for example, it might contain unmatched parentheses) or when some other error occurs during compilation or matching. It is never an error if a string contains no match for a pattern.