You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: wasm_execution.rs
    path of file: ./repos/enigma-core/enigma-runtime-t/src
    
    the code of the file until where you have to start completion: 
use parity_wasm::io::Cursor;
use parity_wasm::elements::{self, Deserialize};
use enigma_tools_t::common::errors_t::{EnclaveError, EnclaveError::*, FailedTaskError, FailedTaskError::*};
use RuntimeResult;
use wasmi::{ImportsBuilder, Module, ModuleInstance, ModuleRef};
pub use gas::{gas_rules, WasmCosts, RuntimeWasmCosts};
use eng_resolver;
use Runtime;
use crate::data::{ContractState};
use enigma_types::StateKey;

use std::boxed::Box;
use std::vec::Vec;
use std::string::{String, ToString};

pub struct WasmEngine {
    pub instance: ModuleRef,
    pub runt
    
    pub fn build_constructor(wasm_code: &[u8]) -> Result<Vec<u8>, EnclaveError> {
        let module = parity_wasm::deserialize_buffer(wasm_code)?;

        let (module, ctor_module) = match pwasm_utils::build(
            module,
            pwasm_utils::SourceTarget::Unknown,
            None,
            &Vec::new(),
            false,
            "49152".parse().expect("New stack size is not valid u32"),
            false,
        ) {
            Ok(v) => v,
            Err(e) => panic!("build_constructor: {:?}", e), // TODO: Return error
        };

        let result;

        if let Some(ctor_module) = ctor_module {
            result = parity_wasm::serialize(ctor_module); /*.map_err(Error::Encoding)*/
        } else {
            result = parity_wasm::serialize(module); /*.map_err(Error::Encoding)*/
        }

        match result {
            Ok(v) => Ok(v),
            Err(e) => panic!("build_constructor: {:?}", e), // TODO: Return Error
        }
    }