class Mail::Body

def split!(boundary)
  self.boundary = boundary
  parts = extract_parts
  # Make the preamble equal to the preamble (if any)
  self.preamble = parts[0].to_s.strip
  # Make the epilogue equal to the epilogue (if any)
  self.epilogue = parts[-1].to_s.strip
  parts[1...-1].to_a.each { |part| @parts << Mail::Part.new(part) }
  self
end