Unpack List<KernelSignature> from HetMap

                              << kernel_signature_var_name << "("

                              << new_var_name << ");\n";

        arg_ctor_list.emplace_back(kernel_signature_var_name);

      } else if (program_arg_types[i].rfind("std::vector<KernelSignature<",

                                            0) == 0) {

        // This is a list of KernelSignatures argument.

        // The one in HetMap is the vector of function pointers represented as a

        // hex string.

        const std::string new_var_name =

            "__temp_kernel_ptr_vector_var__" + std::to_string(var_counter++);

        // Retrieve the list of function pointer from the HetMap

        ref_type_copy_decl_ss << "auto " << new_var_name

                              << " = args.get<std::vector<std::string>>(\""

                              << program_parameters[i] << "\");\n";

        const std::string list_kernel_signature_var_name =

            "__temp_kernel_signature_var__" + std::to_string(var_counter++);

        // Declare the vector of kernel signatures

        ref_type_copy_decl_ss << program_arg_types[i] << " "

                              << list_kernel_signature_var_name << ";\n";

        // Construct the list from function pointers

        ref_type_copy_decl_ss << "std::vector<void*> temp_fn_ptrs(" << new_var_name << ".size());\n";

        ref_type_copy_decl_ss << "int fn_idx = 0;\n";

        ref_type_copy_decl_ss << "for (const auto& ptr_str: " << new_var_name << ") {\n";

        ref_type_copy_decl_ss << "temp_fn_ptrs[fn_idx] = (void *) strtoull(ptr_str.c_str(), nullptr, 16);\n";

        ref_type_copy_decl_ss <<  list_kernel_signature_var_name << ".emplace_back(temp_fn_ptrs[fn_idx++]);\n";

        ref_type_copy_decl_ss << "}\n";

        arg_ctor_list.emplace_back(list_kernel_signature_var_name);

      } else {

        // Otherwise, just unpack the arg inline in the ctor call.

        std::stringstream ss;