Get orig prefx in virtualenv

get_orig_prefix.py

def get_orig_prefix():
    """
    read orig-prefix.txt and return it
    """
    orig_prefix_txt = normpath(abspath(join(get_python_lib(), '..', 'orig-prefix.txt')))
    print orig_prefix_txt
    try:
        with open(orig_prefix_txt) as f:
            path = f.readline().strip()
            return path
    except:
        pass