@Nullable
  @Contract(pure = true)
  private static PsiLocalVariable extractVariable(@Nullable PsiStatement statement) {
    PsiDeclarationStatement declarationStatement = tryCast(statement, PsiDeclarationStatement.class);
    if (declarationStatement == null) return null;
    PsiElement[] elements = declarationStatement.getDeclaredElements();
    if (elements.length != 1) return null;
    return tryCast(elements[0], PsiLocalVariable.class);
  }
@Nullable
  @Contract(pure = true)
  private static PsiLocalVariable extractVariable(@Nullable PsiStatement statement)