-- | A 'Builder' for a 'DTD'.
buildDTD (DTD decl cmps) = buildMaybe buildDTDTextDecl decl <>
  mconcat (map ((<> newline) . buildDTDComponent) cmps)
buildDTD (DTD decl cmps) = buildMaybe buildDTDTextDecl decl <>
  mconcat (map ((<> newline) . buildDTDComponent) cmps)
buildDTD (DTD decl cmps) = buildMaybe buildDTDTextDecl decl <>
  mconcat (map ((<> newline) . buildDTDComponent) cmps)