Siwei Tang

### What happened? In https://github.com/apache/beam/blob/611676d108b26ee378a2b0c128c855017d162772/sdks/python/apache_beam/io/gcp/bigquery.py#L286, the documentation states that the chain operation for file loads is ```return (result.load_jobid_pairs, result.copy_jobid_pairs) | beam.Flatten()``` In fact, according to https://github.com/apache/beam/blob/611676d108b26ee378a2b0c128c855017d162772/sdks/python/apache_beam/io/gcp/bigquery.py#L2230 and https://github.com/apache/beam/blob/611676d108b26ee378a2b0c128c855017d162772/sdks/python/apache_beam/io/gcp/bigquery.py#L2234, it should...

Grind75 leetcode difficulty error

1

According to leetcode, question Lowest Common Ancestor of a Binary Search Tree should be medium instead of easy.