[An extra null pointer check is not needed in functions](https://isocpp.org/wiki/faq/freestore-mgmt#delete-handles-null) like the following. - [CTxDB](https://github.com/okcashpro/okcash/blob/6be76e39c2e028d5c231d1f6e20393ca8dd98e0b/src/txdb-leveldb.h#L37) - [SecureMessage](https://github.com/okcashpro/okcash/blob/6be76e39c2e028d5c231d1f6e20393ca8dd98e0b/src/smessage.h#L75) - [Table::Open](https://github.com/okcashpro/okcash/blob/6be76e39c2e028d5c231d1f6e20393ca8dd98e0b/src/leveldb/table/table.cc#L81)
