Python Regular expression, small sample works but not on file

[Acernz]

Hi Experts,

Small sample:
<span id="AccordionHeaderText52741" class="clsAccordionHeaderText"><a id="AccordionHeaderTab52741" tabIndex="101" onkeydown="websys_ToggleAccordion('52741',event);">Billing</a></span>

a regular expression, which works in https://regex101.com/ is

",event\);\">(.*)<\/a.*"

The same works in python editor which pulls out "Billing"

import re
with open('testregpad.txt') as f:
    for line in f:
        match = re.search('event\);\">(.*)<\/a.*', line)
print(match.group(1))

output: Billing

But when I provide the entire page source to pull all the matching strings in the complete file, the code is failing.
Here is the error message both in sublime and jupyter.

Error:
traceback (most recent call last):
  File "C:\Data\Academic\Python\RegExtractData", line 5, in <module>
    print(match.group(1))
AttributeError: 'NoneType' object has no attribute 'group'
[Finished in 120ms]

Help is appreciated.