Binary package “postgresql-plpython3-10” in ubuntu bionic

PL/Python 3 procedural language for PostgreSQL 10

 PL/Python 3 enables an SQL developer to write procedural language functions
 for PostgreSQL 10 in Python 3. You need this package if you have any
 PostgreSQL 10 functions that use the languages plpython3 or plpython3u.
 .
 PostgreSQL is an object-relational SQL database management system.