This example implements an IHE ITI-21 transaction, (aka PDQ).
A simple MLLP server accepts QBP_Q21 messages only, returning a NAK message otherwise.

server.py: The MLLPServer implementation with the PDQSupplier handler and the error handler.
    It launches the server, bound by default to localhost:6789.
client.py: TCP client that sends a PDQ query looking for patients with surname SMITH.

=== HOW TO USE ===

Run the TCP server by executing:

python server.py

then execute the client:

python client.py

