input: Write a python function to split a sentence into groups of up to 50 words.
  assert split_into_groups("The W3C HTML 4.01 specification defines the language used to create web pages, including elements such as <head>, <body>, <div> and <span>, as well as the structure of the web document as it appears in a web browser.") == ["The W3C HTML 4.01 specification defines the language used to create web pages, including elements such as <head>, <body>, <div> and <span>, as well as the structure of the web document as it appears in a web browser."]
  assert split_into_groups("Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.") == ["Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.", "Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."]
  assert split_into_groups("This is a short sentence.") == ["This is a short sentence."]
output: def split_into_groups(sentence):
      words = sentence.split()
      groups = []
      i = 0
      while i < len(words):
          group = " ".join(words[i:i+50])
          groups.append(group)
          i += 50
      return groups