@Nullable
  private List<PreContract> handleSingleStatement(LighterASTNode statement) {
    if (statement.getTokenType() == RETURN_STATEMENT) {
      LighterASTNode returned = findExpressionChild(myTree, statement);
      return getLiteralConstraint(returned) != null ? emptyList() : handleDelegation(returned, false);
    }
    if (statement.getTokenType() == EXPRESSION_STATEMENT) {
      LighterASTNode expr = findExpressionChild(myTree, statement);
      return expr != null && expr.getTokenType() == METHOD_CALL_EXPRESSION ? handleDelegation(expr, false) : null;
    }
    return null;
  }
@Nullable
  private List<PreContract> handleSingleStatement(LighterASTNode statement)