ConnectionPool.get_connection does not raise mariadb.PoolError

Steps to reproduce

1. set enviroment variables to allow login to server (see attached file)
2. Run python example

The example code initializes a ConnectionPool with 3 connections and calls get_connection() 4 times.

Expected outcome

As the documentation says, get_connection should raise a PoolError, because no connection is available:

ConnectionPool.get_connection()
Returns a connection from the connection pool or raises a PoolError exception if a connection is not available.

Actual outcome

get_connection() does not raise PoolError but returns None

Workaround

Do not catch PoolError but test return value:

conn = pool.get_connection()

if not conn:

    # put error handling here

Remarks

There is probably much code which relies on the current implementation, so its probably better to change the documentation.

There is a test case test_connection_pool_maxconn in .\testing\test\integration\test_pooling.py but it does not assert that a PoolError is raised.