AttributeError: 'NoneType' object has no attribute 'group'

This error occurs when you try to use the `group()` method on a `NoneType` object. The `group()` method is a regular expression method that returns the matched substring.

For example, if you have a regular expression pattern that matches a specific string in a text, you can use the `group()` method to get the matched substring. However, if the pattern does not match any substring, the method returns `None`, which is a `NoneType` object.

To fix this error, you need to check if the regular expression pattern has matched any substring before using the `group()` method. You can use the `match()` or `search()` method to check if the pattern matches any substring and then use the `group()` method on the matched object.

Here is an example of how to use the `search()` method to avoid the `NoneType` error:

import re

text = "Hello, World!"
pattern = r"Hello"

match = re.search(pattern, text)
if match:
    print(match.group())  # This will print "Hello"
else:
    print("Pattern not found")

In this example, the `search()` method is used to find the substring "Hello" in the text. If the pattern is found, the `group()` method is used to get the matched substring. If the pattern is not found, the `else` block is executed and "Pattern not found" is printed.