input: from typing import List
  
  
  def replace_all_occurrences(str: str, char: str, replacement: str) -> str:
      """ Replace all occurrences of a character in a string with the provided replacement character.
      >>> replace_all_occurrences("Hello World!", 'l', 'X')
      'HeXXo WorXd!'
      >>> replace_all_occurrences("Banana", 'a', 'Z')
      'BZnZnZ'
      """
      return str.replace(char, replacement)
output:     return str.replace(char, replacement)