How to use the @sinonjs/commons.functionName function in @sinonjs/commons

function createSpy(func) {
    var name;
    var funk = func;

    if (typeof funk !== "function") {
        funk = function() {
            return;
        };
    } else {
        name = functionName(funk);
    }

    var proxy = createProxy(funk, funk);

    // Inherit spy API:
    extend.nonEnum(proxy, spyApi);
    extend.nonEnum(proxy, {
        displayName: name || "spy",
        fakes: [],
        instantiateFake: createSpy,
        id: "spy#" + uuid++
    });
    return proxy;
}

var fnStub =
            pop(
                sort(matchings, function(a, b) {
                    return a.matchingArguments.length - b.matchingArguments.length;
                })
            ) || proxy;
        return getCurrentBehavior(fnStub).invoke(this, arguments);
    }

    proxy = createProxy(functionStub, originalFunc || functionStub);
    // Inherit spy API:
    extend.nonEnum(proxy, spy);
    // Inherit stub API:
    extend.nonEnum(proxy, stub);

    var name = originalFunc ? functionName(originalFunc) : null;
    extend.nonEnum(proxy, {
        fakes: [],
        instantiateFake: createStub,
        displayName: name || "stub",
        defaultBehavior: null,
        behaviors: [],
        id: "stub#" + uuid++
    });

    return proxy;
}

var fnStub =
            pop(
                sort(matchings, function(a, b) {
                    return a.matchingArguments.length - b.matchingArguments.length;
                })
            ) || proxy;
        return getCurrentBehavior(fnStub).invoke(this, arguments);
    }

    proxy = createProxy(functionStub, originalFunc || functionStub);
    // Inherit spy API:
    extend.nonEnum(proxy, spy);
    // Inherit stub API:
    extend.nonEnum(proxy, stub);

    var name = originalFunc ? functionName(originalFunc) : null;
    extend.nonEnum(proxy, {
        fakes: [],
        instantiateFake: createStub,
        displayName: name || "stub",
        defaultBehavior: null,
        behaviors: [],
        id: "stub#" + uuid++
    });

    return proxy;
}

function constructorName(f, object) {
    var name = functionName(object && object.constructor);
    var excludes = f.excludeConstructors || formatio.excludeConstructors;

    var i, l;
    for (i = 0, l = excludes.length; i < l; ++i) {
        if (typeof excludes[i] === "string" && excludes[i] === name) {
            return "";
        } else if (excludes[i].test && excludes[i].test(name)) {
            return "";
        }
    }

    return name;
}

function getCallbackError(behavior, func, args) {
    if (behavior.callArgAt < 0) {
        var msg;

        if (behavior.callArgProp) {
            msg =
                functionName(behavior.stub) +
                " expected to yield to '" +
                valueToString(behavior.callArgProp) +
                "', but no object with such a property was passed.";
        } else {
            msg = functionName(behavior.stub) + " expected to yield, but no callback was passed.";
        }

        if (args.length > 0) {
            msg += " Received [" + join(args, ", ") + "]";
        }

        return msg;
    }

    return "argument at index " + behavior.callArgAt + " is not a function: " + func;
}

function getCallbackError(behavior, func, args) {
    if (behavior.callArgAt < 0) {
        var msg;

        if (behavior.callArgProp) {
            msg =
                functionName(behavior.stub) +
                " expected to yield to '" +
                valueToString(behavior.callArgProp) +
                "', but no object with such a property was passed.";
        } else {
            msg = functionName(behavior.stub) + " expected to yield, but no callback was passed.";
        }

        if (args.length > 0) {
            msg += " Received [" + join(args, ", ") + "]";
        }

        return msg;
    }

    return "argument at index " + behavior.callArgAt + " is not a function: " + func;
}

function: function(m, expectation, message) {
        m.test = expectation;
        m.message = message || "match(" + functionName(expectation) + ")";
    },
    number: function(m, expectation) {

function getCallbackError(behavior, func, args) {
    if (behavior.callArgAt < 0) {
        var msg;

        if (behavior.callArgProp) {
            msg =
                functionName(behavior.stub) +
                " expected to yield to '" +
                valueToString(behavior.callArgProp) +
                "', but no object with such a property was passed.";
        } else {
            msg = functionName(behavior.stub) + " expected to yield, but no callback was passed.";
        }

        if (args.length > 0) {
            msg += " Received [" + join(args, ", ") + "]";
        }

        return msg;
    }

    return "argument at index " + behavior.callArgAt + " is not a function: " + func;
}