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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 tell(self):
 """Return the file's current position. Returns: int, file's current position in bytes. """

        self._check_open_file()
        if self._flushes_after_tell():
            self.flush()

        if not self._append:
            return self._io.tell()
        if self._read_whence:
            write_seek = self._io.tell()
            self._io.seek(self._read_seek, self._read_whence)
            self._read_seek = self._io.tell()
            self._read_whence = 0
            self._io.seek(write_seek)
        return self._read_seek