Final answer:
To catch a KeyError and print a specific message, modify the code with 'except KeyError: print("A KeyError occurred!")'
Step-by-step explanation:
The code should be modified as follows:
except KeyError:
print("A KeyError occurred!")
The code 'except KeyError' will catch any KeyError that occurs and the message 'A KeyError occurred!' will be printed. This specific modification will ensure that only KeyError is caught and not any other type of error.