strange situation

Hi, I'm facing a strange situation. These FIND and REPLACE do not work. That is, finding works, but replacing does not work.

In these 3 situations, I have to replace an annuit regex with (empty space). See that '' there
If at re.findall I put any simple regex, for example an html tag <div> then the replacement is done perfectly.
But if it is a different kind of regex, such as the ones below, the replacement is no longer done. I mean nothing happens ...


if len(re.findall('(?!<p>).+?(?<!</p>)$', page_text)) != 0:
   page_text = re.sub('(?!<p>).+?(?<!</p>)$', '', page_text)
   counter_img += 1
OR

if len(re.findall('^\s+</p>', page_text)) != 0:
   page_text = re.compile(r'', page_text)
   counter_img += 1

OR

if len(re.findall('\n\s*', page_text)) != 0:
   page_text = re.sub('\n\s*', '', page_text)
   counter_img += 1