@Nullable
  public static PsiType getReturnType(@NotNull final List<? extends GrSignature> signatures, @NotNull GrMethodCall expr) {
    return getReturnType(signatures, PsiUtil.getArgumentTypes(expr.getInvokedExpression(), true), expr);
  }
@Nullable
  public static PsiType getReturnType(@NotNull final List<? extends GrSignature> signatures, @NotNull GrMethodCall expr)