def _cfstr(py_bstr):
    """
    Given a Python binary data, create a CFString.
    The string must be CFReleased by the caller.
    """
    c_str = ctypes.c_char_p(py_bstr)
    cf_str = CoreFoundation.CFStringCreateWithCString(
        CoreFoundation.kCFAllocatorDefault,
        c_str,
        CFConst.kCFStringEncodingUTF8,
    )
    return cf_str

    Given a Python binary data, create a CFString.
    The string must be CFReleased by the caller.
    
lib/urllib3/contrib/_securetransport/low_level.py