The implementation currently used is available in the `~psycopg.pq.__impl__`
module constant.
-At import, Psycopg 3 will try to use the best implementation available and
-will fail if none is usable. You can force the use of a specific
+At import time, Psycopg 3 will try to use the best implementation available
+and will fail if none is usable. You can force the use of a specific
implementation by exporting the env var :envvar:`PSYCOPG_IMPL`: importing the
library will fail if the requested implementation is not available::