The function takes a string input and performs a Caesar-like alphabetic shift on each character in the string, with the exception of digits, which are preserved as-is. The function appears to shift the characters by a fixed distance.

[CODE]:
```python
def Caesar_shift(input_string, shift):
    output_string = ""
    for ch in input_string:
        if ch.isalpha():
            shift_by = shift % 26
            if ch.isupper():
                output_string += chr((ord(ch) - ord('A') + shift_by) % 26 + ord('A'))
            else:
                output_string += chr((ord(ch) - ord('a') + shift_by) % 26 + ord('a'))
        elif ch.isdigit():
            output_string += ch
        else:
            output_string += ch
    return output_string
```

We should determine the shift distance used by the function:

COMMAND: PYTHON(./temp/function.py "a" "b" "c" "A" "B" "C")