input: Write a function that takes a list of strings and returns a new list with all the strings converted to uppercase.
  
  def convert_to_upper(strings):
   return [s.upper() for s in strings]
   
  assert convert_to_upper(["hello", "world"])==["HELLO", "WORLD"]
  assert convert_to_upper(["Python", "is", "fun"])==["PYTHON", "IS", "FUN"]
  assert convert_to_upper([])==[]
output: def convert_to_upper(strings):
   return [s.upper() for s in strings]