process_all.py

def process_all(text):
    text = remove_tags(text)
    text = process_single_quote(text)
    text = decontract(text)
    text = remove_special_chars(text)
    text = remove_more_than_single_space(text)
    text = text.lower()
    text = stem_sentence(text)
    return text

This will be way shorter!!
def process_all(text):
funcs = [remove_tags,process_single_quote,decontract,remove_special_chars,remove_more_than_single_space,lower,stem_sentence]
for f in funcs:
text = f(text)
return text