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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def simplify_expression(txt):
 """Remove all unecessary whitespace and some very usual space"""

    minimal = re.sub(r'\s', ' ',
                     re.sub(r'\s(?=\W)', '',
                            re.sub(r'(?<=\W)\s', '',
                                   txt.strip())))
    # add space before some "(" and after some ")"
    return re.sub(r'\)(?=\w)', ') ',
                  re.sub(r'(,|\b(?:{}))\('.format('|'.join(RESERVED_WORDS)), '\\1 (', minimal)
                  )