code: def build_doctype(qualifiedName, publicId=None, systemId=None, internalSubset=None):
      
      doctype = ElifeDocumentType(qualifiedName)
      doctype._identified_mixin_init(publicId, systemId)
      if internalSubset:
          doctype.internalSubset = internalSubset
      return doctype
docs: Instantiate an ElifeDocumentType, a subclass of minidom.DocumentType, with
      some properties so it is more testable