input: Write a function to format a given piece of text with different options for font-style, size, and color. The function should return a string that contains the formatted text. If no options are provided, the function should use default values for font-style, size, and color.
  def format_text(text, font="Times New Roman", size='14px', color='#000000'):
    return f"<span style='font-family: {font}; font-size: {size}; color: {color};'>{text}</span>"
  
  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.', 'Arial', '16px', '#FF0000') == "<span style='font-family: Arial; font-size: 16px; color: #FF0000;'>Aliquam non velit sit amet arcu placerat vulputate a ut nibh.</span>"
  assert format_text('') == "<span style='font-family: Times New Roman; font-size: 14px; color: #000000;'></span>"
output: def format_text(text, font="Times New Roman", size='14px', color='#000000'):
    return f"<span style='font-family: {font}; font-size: {size}; color: {color};'>{text}</span>"