compatible with pandas 1.2

[zhuoqiang]

change some incompatible pandas usage to support working with pandas v1.2

• SpecificationError: nested renamer is not supported while agg(): have to use agg(**dict) instead
• KeyError: "Passing list-likes to .loc or [] with any missing labels is no longer supported: have to use reindex instead
• OverflowError: cannot convert float infinity to integer. because inf is not consider to be na value by default