input: Write a function to format a given piece of text with different options for font-style, size, and color.
  def format_text(text, font="Times New Roman", size='14px', color='#000000'):
    return "<span style='font-family: {} font-size: {} color: {}'>{}</span>".format(font, size, color, text)
  
  assert format_text('Lorem ipsum dolor sit amet, consectetur adipiscing elit.') == "<span style='font-family: Times New Roman font-size: 14px color: #000000'>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</span>"
  assert format_text('Aliquam non velit sit amet arcu placerat vulputate a ut nibh.', font="Arial", size='12px', color='#FF0000') == "<span style='font-family: Arial font-size: 12px color: #FF0000'>Aliquam non velit sit amet arcu placerat vulputate a ut nibh.</span>"
  assert format_text('', size='10px') == "<span style='font-family: Times New Roman font-size: 10px color: #000000'></span>"
output: def format_text(text, font="Times New Roman", size='14px', color='#000000'):
    return "<span style='font-family: {}; font-size: {}; color: {};'>{}</span>".format(font, size, color, text)