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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 _init_externals():
 """Initialize external projects by putting them into the path"""

    if __version__ == 'git':
        sys.path.insert(0, osp.join(osp.dirname(__file__), 'ext', 'gitdb'))

    try:
        import gitdb
    except ImportError:
        raise ImportError("'gitdb' could not be found in your PYTHONPATH")