code: def yesno(message, default='yes', suffix=' '):
      
      if default == 'yes':
          yesno_prompt = '[Y/n]'
      elif default == 'no':
          yesno_prompt = '[y/N]'
      else:
          raise ValueError("default must be 'yes' or 'no'.")
  
      if message != '':
          prompt_text = "{0} {1}{2}".format(message, yesno_prompt, suffix)
      else:
          prompt_text = "{0}{1}".format(yesno_prompt, suffix)
  
      while True:
          response = get_input(prompt_text).strip()
          if response == '':
              return True
          else:
              if re.match('^(y)(es)?$', response, re.IGNORECASE):
                  if default == 'yes':
                      return True
                  else:
                      return False
              elif re.match('^(n)(o)?$', response, re.IGNORECASE):
                  if default == 'no':
                      return True
                  else:
                      return False
docs: Prompt user to answer yes or no. Return True if the default is chosen,
       otherwise False.