text: '''
  Error handling by raising an error
  100xp
  
  Another way to raise an error is by using raise. In this exercise, you will
  add a raise statement to the shout_echo() function you defined before to raise
  an error message when the value supplied by the user to the echo argument is
  less than 0.
  
  The call to shout_echo() uses valid argument values. To test and see how the
  raise statement works, simply change the value for the echo argument to a
  negative value. Don't forget to change it back to valid values to move on to
  the next exercise!
  
  Instructions
  -Complete the if statement by checking if the value of echo is less than 0.
  -In the body of the if statement, add a raise statement that raises the error
  message 'echo must be greater than or equal to 0' when the value supplied by the user to
  echo is less than 0.
  '''
  # Define shout_echo
  def shout_echo(word1, echo=1):
      """Concatenate echo copies of word1 and three
      exclamation marks at the end of the string."""
  
      # Raise an error with raise
      if echo < 0:
          raise ValueError('echo must be greater than or equal to 0')
  
      # Concatenate echo copies of word1 using *: echo_word
      echo_word = word1 * echo
  
      # Concatenate '!!!' to echo_word: shout_word
      shout_word = echo_word + '!!!'
  
      # Return shout_word
      return shout_word
  
  # Call shout_echo
  shout_echo("particle", echo=5)
  