Define a Python function that checks whether in a given string every instance of one character always precedes every instance of another.
Write a Python function, `precedence`, to verify the order in which two characters appear in a given string. The function should accept three params - a string `s`, and two characters `first` and `second`. If every instance of `first` precedes every instance of `second` in the string `s`, the function should return `True`, and `False` otherwise. ### Parameters - `s` : A string where we have to look for the characters `first` and `second`. - `first` : The character that should appear first in `s`. - `second` : The character that should appear after `first` in `s`. ### Return Value - If all instances of `first` come before any instances of `second` in `s`, return `True`. - If the above condition is not satisfied, return `False`. ### Examples ```python precedence("a rabbit jumps joyfully", "a", "j") # Expected output: True precedence("knaves knew about waterfalls", "k", "w") # Expected output: True precedence("happy birthday", "a", "y") # Expected output: False precedence("precarious kangaroos", "k", "a") # Expected output: False ```