input: Write a function to determine if a given character is present in a given string. Return True if the character is found, otherwise return False.
  
  assert serach_char("Hello", 'l')==True
  assert serach_char("Hello", 'o')==True
  assert serach_char("Hello", 'x')==False
  assert serach_char("", 'a')==False
output: def search_char(s, c):
      return c in s