def make_path_relative(path, rel_to):
    path_filename = os.path.basename(path)
    path = os.path.dirname(path)
    path = os.path.normpath(os.path.abspath(path))
    rel_to = os.path.normpath(os.path.abspath(rel_to))
    path_parts = path.strip(os.path.sep).split(os.path.sep)
    rel_to_parts = rel_to.strip(os.path.sep).split(os.path.sep)
    while path_parts and rel_to_parts and path_parts[0] == rel_to_parts[0]:
        path_parts.pop(0)
        rel_to_parts.pop(0)
    full_parts = ['..']*len(rel_to_parts) + path_parts + [path_filename]
    if full_parts == ['']:
        return '.' + os.path.sep
    return os.path.sep.join(full_parts)
Make a filename relative, where the filename path, and it is
dataset/ETHPy150Open balanced/status.balancedpayments.com/venv/lib/python2.7/site-packages/pip-1.3.1-py2.7.egg/pip/util.py/make_path_relative