How to use the ethereum-types.AbiType.Function function in ethereum-types

        const methodAbis = contractAbi.filter((abi: AbiDefinition) => abi.type === AbiType.Function) as MethodAbi[];
        // Sort method Abis into alphabetical order, by function signature

const methodAbi = _.find(this.abi, (abiDefinition: AbiDefinition) => {
            if (abiDefinition.type !== AbiType.Function) {
                return false;
            }
            // tslint:disable-next-line:no-unnecessary-type-assertion
            const abiFunctionSignature = new AbiEncoder.Method(abiDefinition as MethodAbi).getSignature();
            if (abiFunctionSignature === functionSignature) {
                return true;
            }
            return false;
        }) as MethodAbi;
        return methodAbi;

_.map(abiArray, (abi: AbiDefinition) => {
            switch (abi.type) {
                case AbiType.Event:
                    // tslint:disable-next-line:no-unnecessary-type-assertion
                    this._addEventABI(abi as EventAbi, ethersInterface);
                    break;

                case AbiType.Function:
                    // tslint:disable-next-line:no-unnecessary-type-assertion
                    this._addMethodABI(abi as MethodAbi, contractName);
                    break;

                default:
                    // ignore other types
                    break;
            }
        });
    }

            (abiDefinition: AbiDefinition) => abiDefinition.type === AbiType.Function,
        ) as MethodAbi[];