problem in matching in regex

[snippsat]

The regex is not at all right for this task,as you use regex101 on right side it will explain what the regex is doing.

import re

test_str = "These books are good.\nThe weather is nice.\nwhere are you going?\nthe car is green"
pattern = r'^The\s.*'
matches = re.finditer(pattern, test_str, re.MULTILINE)
for match in matches:
    print(match.group()) 

Output:
The weather is nice.

If also want lowercase add re.MULTILINE | re.IGNORECASE

Output:
The weather is nice.
the car is green