human
Solve the following python programming problem given the following code:
def gfm(text) : 
    '
    Prepare text for rendering by a regular Markdown processor.
    ' 
    def indent_code(matchobj) : 
        syntax = matchobj.group (1) 
        code = matchobj.group (2) 
        if syntax : 
            result = (('    :::' + syntax) + '
') 
else : 
            result = '' 
return (result + '
'.join ([('    ' + line) for line in code.split ('
') [: (- 1)]])) 
use_crlf = (text.find ('\r') != (- 1)) 
    if use_crlf : 
        text = text.replace ('\r
', '
') 
text = CODEPATTERN_RE.sub (indent_code, text) 
    (text, code_blocks) = remove_pre_blocks (text) 
    (text, inline_blocks) = remove_inline_code_blocks (text) 
    def italic_callback(matchobj) : 
        s = matchobj.group (0) 
        if (('http:' in s) or ('https:' in s)) : 
            return s 
return s.replace ('_', '\\_') 
text = ITALICSPATTERN_RE.sub (italic_callback, text) 
    text = NAKEDURL_RE.sub ('\\1[\\2](\\2)\\3', text) 
    def newline_callback(matchobj) : 
        if (len (matchobj.group (1)) == 1) : 
            return (matchobj.group (0).rstrip () + '  
') 
else : 
            return matchobj.group (0) 
text = NEWLINE_RE.sub (<MASK>, text) 
    removed_blocks = (code_blocks + inline_blocks) 
    for removed_block in removed_blocks : 
        text = text.replace ('{placeholder}', removed_block, 1) 
if use_crlf : 
        text = text.replace ('
', '\r
') 
return text 
    
    Given the code above, what is a proper replacement for <MASK>?
assistant
#Here is Python program to find ('\r') != (- 1)) 
.
def newline_callback(