input: Write a python function to remove all occurrences of a specified character from a string.
  assert remove_char("hello world", "o") == "hell wrld"
  assert remove_char("foobar", "o") == "fbar"
  assert remove_char("python programming", "p") == "ython rogramming"
output: def remove_char(s: str, char: str) -> str:
      return s.replace(char, "")