There are 2 repositories under s7-communication topic.
Parser of the industrial protocol S7 (S7comm) using Libpcap
The tool for enumerating Siemens S7 PLCs through TCP/IP or LLC network
S7 Communication Library Fully Implemented in Python
A Python3 implementation of Siemens Step7 protocol
LIBNODAVE, a free library to communicate to Siemens S7 PLCs