If you find yourself unable to use particular SNMP feature with the high-level, "oneliner" API, your next step would be to use SNMPv3 engine services through one of the Standard SNMP Applications (RFC3413).
There're a large number of SNMPv3 Native API example scripts on this website. Most of them serve a very specific purpose like talking arbitrary SNMP version or handling particular PDU type. That dedication of features serve the purpose of simplifying example code and easing your studies.
Since all these examples are built on top of common PySNMP components like SNMP engine, asyncore-based I/O dispatcher, configuration datastore, you could always combine parts of the examples for getting a new breed of SNMP application best matching your needs.
SNMP Command Generator Applications:
SNMP Command Responder Applications:
SNMP Notification Originator Applications:
SNMP Notification Receiver Application:
SNMP Proxy Forwarder Application:
For more details on PySNMP programming model and interfaces, please refer to the documentation.