Remove spaces regex
This is not necessary as we can use rstrip, lstrip, and replace.
import re
line = " ab cd "
res = re.sub(r'^\s+', '', line) # leading
print(f"'{res}'")
res = re.sub(r'\s+$', '', line) # trailing
print(f"'{res}'")
both ends:
re.sub(r'\s*(.*)\s*$', r'\1', line) # " abc " => "abc " because of the greediness
re.sub('^\s*(.*?)\s*$', '\1', line) # " abc " => "abc" minimal match