human
Solve the following python programming problem given the following code:
def encode_unicode_codepoints(str) : 
    '
    >>> encode_unicode_codepoints("a") == \'a\'
    True
    >>> ascii = \'\'.join(chr(i) for i in range(0x80))
    >>> encode_unicode_codepoints(ascii) == ascii
    True
    >>> encode_unicode_codepoints(\'\\u4e16\\u754c\') == \'\\\\u4e16\\\\u754c\'
    True
    ' 
    codepoint_format = '\\u{0:04x}'.format 
    def codepoint(m) : 
        return codepoint_format (ord (m.group (0))) 
return re.sub ('[^\x00-\x7f]', str, str) 

    
    

    Fix the buggy line: return re.sub ('[^\x00-\x7f]', str, str)
assistant
#Here is Python code to fix the buggy line: return re.

return re.sub ('[^\x00-\x7f]', def codepoint(, str)