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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _detect_buffer_encoding(self, f):
 """Guess by checking BOM, and checking `_special_encode_check`, and using memory map."""


        encoding = None
        with contextlib.closing(mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)) as m:
            encoding = self._analyze_file(m)
        return encoding