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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:
 async def seek(self, pos, whence=sync_io.SEEK_SET):
 """Move to new file position. Argument offset is a byte count. Optional argument whence defaults to SEEK_SET or 0 (offset from start of file, offset should be >= 0); other values are SEEK_CUR or 1 (move relative to current position, positive or negative), and SEEK_END or 2 (move relative to end of file, usually negative, although many platforms allow seeking beyond the end of a file). Note that not all file objects are seekable. """

        return self._stream.seek(pos, whence)