What Scheme implementation am I running?

Given a Scheme shell/interpreter, what command could output its implementation (R5RS, R6RS or whatever). For example, I have mit-scheme installed in a Debian machine. How could I discover what implementation it is? I'm thinking in terms of Python. If you have a Python shell, you can either run import sys print(sys.version) to print the version directly, or test it with: print 'abc' to see if it runs (it would run in case of Python2).