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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_installer_url(version=None):
 """Get argument to give to ``pip`` to install HPCBench. """

    version = version or hpcbench.__version__
    version = str(version)
    if '.dev' in version:
        git_rev = 'master'
        if 'TRAVIS_BRANCH' in os.environ:
            git_rev = version.split('+', 1)[-1]
            if '.' in git_rev:  # get rid of date suffix
                git_rev = git_rev.split('.', 1)[0]
            git_rev = git_rev[1:]  # get rid of scm letter
        return 'git+{project_url}@{git_rev}#egg=hpcbench'.format(
            project_url='http://github.com/BlueBrain/hpcbench',
            git_rev=git_rev or 'master',
        )
    return 'hpcbench=={}'.format(version)