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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 save(self, incoming_stream, size_limit=None, size=None, chunk_size=None, progress_callback=None):
 """Save file in the file system."""

        fp = self.open(mode='wb')
        try:
            bytes_written, checksum = self._write_stream(
                incoming_stream, fp, chunk_size=chunk_size,
                progress_callback=progress_callback,
                size_limit=size_limit, size=size)
        except Exception:
            fp.close()
            self.delete()
            raise
        finally:
            fp.close()

        self._size = bytes_written

        return self.fileurl, bytes_written, checksum