input: Write a function to split a paragraph into a list of words.
  assert split_paragraph("Thomas Jefferson was an American statesman, diplomat, lawyer, architect, philosopher and Founding Father who served as the third president of the United States from 1801 to 1809.") == ["Thomas", "Jefferson", "was", "an", "American", "statesman,", "diplomat,", "lawyer,", "architect,", "philosopher", "and", "Founding", "Father", "who", "served", "as", "the", "third", "president", "of", "the", "United", "States", "from", "1801", "to", "1809."]
  assert split_paragraph("Hello world!") == ["Hello", "world!"]
  assert split_paragraph("Python is great for data science.") == ["Python", "is", "great", "for", "data", "science."]
output: def split_paragraph(paragraph):
      return paragraph.split()