input: Write a function to format a given piece of text with different options for font-style, size, and color. The function should return the formatted text as a string with the specified font, size, and color. 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 "<span style='font-family: {} font-size: {} color: {}'>{}</span>".format(font, size, color, text)
  
  assert format_text('Lorem ipsum dolor sit amet')== "<span style='font-family: Times New Roman font-size: 14px color: #000000'>Lorem ipsum dolor sit amet</span>"
  assert format_text('Aliquam non velit sit amet', 'Arial', '16px', '#FF0000')== "<span style='font-family: Arial font-size: 16px color: #FF0000'>Aliquam non velit sit amet</span>"
  assert format_text('Integer ut lectus vel nisi consequat', size='18px')== "<span style='font-family: Times New Roman font-size: 18px color: #000000'>Integer ut lectus vel nisi consequat</span>"
  assert format_text('Aliquam non velit sit amet', color='#00FF00')== "<span style='font-family: Times New Roman font-size: 14px color: #00FF00'>Aliquam non velit sit amet</span>"
  assert format_text('Integer ut lectus vel nisi consequat', font='Verdana')== "<span style='font-family: Verdana font-size: 14px color: #000000'>Integer ut lectus vel nisi consequat</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)