@Nullable
    static Declaration create(@NotNull PsiDeclarationStatement declaration) {
      PsiElement[] declared = declaration.getDeclaredElements();
      if (declared.length != 1) return null;
      PsiVariable lhs = tryCast(declared[0], PsiVariable.class);
      if (lhs == null) return null;
      PsiExpression rhs = lhs.getInitializer();
      return rhs == null ? null : new Declaration(lhs, rhs);
    }
@Nullable
    static Declaration create(@NotNull PsiDeclarationStatement declaration)