Python - the meaning of "!"

Question

While studying Python, I run the following example code regarding function.wrap.

def trace(func):
    def wrapper(*args, **kwargs):
        result = func(*args, **kwargs)
        print(f'{func.__name__}({args!r}, {kwargs!r}) '
              f'-> {result!r}')
        return result
    return wrapper

@trace
def fibonacci(n):
    """Return the n-th Fibonacci number"""
    if n in (0, 1):
        return n
    return (fibonacci(n - 2) + fibonacci(n - 1))

fibonacci(4)

In this code, I don't understand print (f'{func.__name__} ({args!r}, {kwargs!r}) 'f'-> {result!r}') in trace function.

What does this !r mean?

Even without this !r, the results are the same.

• Result

fibonacci(4)

>>>
fibonacci((0,), {}) -> 0
fibonacci((1,), {}) -> 1
fibonacci((2,), {}) -> 1
fibonacci((1,), {}) -> 1
fibonacci((0,), {}) -> 0
fibonacci((1,), {}) -> 1
fibonacci((2,), {}) -> 1
fibonacci((3,), {}) -> 2
fibonacci((4,), {}) -> 3