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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 pip(filename):
 """Parse pip reqs file and transform it to setuptools requirements."""

    requirements = []
    for line in open(join(ROOT, 'requirements', filename)):
        line = line.strip()
        if not line or '://' in line:
            continue
        match = RE_REQUIREMENT.match(line)
        if match:
            requirements.extend(pip(match.group('filename')))
        else:
            requirements.append(line)
    return requirements