@Override
    @Nullable
    public PsiElement resolve() {
      final String prefix = getCanonicalText();
      XmlTag tag = PsiTreeUtil.getParentOfType(getElement(), XmlTag.class);
      while (tag != null) {
        if (tag.getLocalNamespaceDeclarations().containsKey(prefix)) {
          final XmlAttribute attribute = tag.getAttribute("xmlns:" + prefix, "");
          final TextRange textRange = TextRange.from("xmlns:".length(), prefix.length());
          return new SchemaPrefix(attribute, textRange, prefix);
        }
        tag = tag.getParentTag();
      }
      return null;
    }
@Override
    @Nullable
    public PsiElement resolve()