Change the stream position to the given byte offset.
offset
The stream position, relative to 'whence'.
whence
The relative position to seek from.
The offset is interpreted relative to the position indicated by
whence. Values for whence are:
* os.SEEK_SET or 0 -- start of stream (the default); offset should
be zero or positive
* os.SEEK_CUR or 1 -- current stream position; offset may be
negative
* os.SEEK_END or 2 -- end of stream; offset is usually negative
Return the new absolute position.
3.3: Some operating systems could support additional values, like os.SEEK_HOLE or os.SEEK_DATA. The valid values for a file could depend on it being open in text or binary mode.