How to use the @aws-cdk/cfnspec.schema.isMapProperty function in @aws-cdk/cfnspec

// render the union of all item types
    if (schema.isCollectionProperty(propSpec)) {
      // render the union of all item types
      const itemTypes = genspec.specTypesToCodeTypes(resourceContext, itemTypeNames(propSpec));

      // 'tokenizableType' operates at the level of rendered type names in TypeScript, so stringify
      // the objects.
      const renderedTypes = itemTypes.map(t => this.renderCodeName(resourceContext, t));
      if (!tokenizableType(renderedTypes) && propName !== 'Tags') {
        // Always accept a token in place of any list element (unless the list elements are tokenizable)
        itemTypes.push(genspec.TOKEN_NAME);
      }

      const union = this.renderTypeUnion(resourceContext, itemTypes);

      if (schema.isMapProperty(propSpec)) {
        alternatives.push(`{ [key: string]: (${union}) }`);
      } else {
        // To make TSLint happy, we have to either emit: SingleType[] or Array
        if (union.indexOf('|') !== -1) {
          alternatives.push(`Array<${union}>`);
        } else {
          alternatives.push(`${union}[]`);
        }
      }
    }

    // Yes, some types can be both collection and scalar. Looking at you, SAM.
    if (schema.isScalarPropery(propSpec)) {
      // Scalar type
      const typeNames = scalarTypeNames(propSpec);
      const types = genspec.specTypesToCodeTypes(resourceContext, typeNames);

export function typeDispatch(resourceContext: CodeName, spec: schema.Property, visitor: PropertyVisitor): T {
  const scalarTypes = specTypesToCodeTypes(resourceContext, scalarTypeNames(spec));
  const itemTypes = specTypesToCodeTypes(resourceContext, itemTypeNames(spec));

  if (scalarTypes.length && itemTypes.length) {
    // Can accept both a list and a scalar
    return visitor.visitListOrScalar(scalarTypes, itemTypes);
  } else if (schema.isCollectionProperty(spec)) {
    if (schema.isMapProperty(spec)) {
      if (itemTypes.length > 1) {
        return visitor.visitUnionMap(itemTypes);
      } else {
        return visitor.visitMap(itemTypes[0]);
      }
    } else {
      if (itemTypes.length > 1) {
        return visitor.visitUnionList(itemTypes);
      } else {
        return visitor.visitList(itemTypes[0]);
      }
    }
  } else {
    if (scalarTypes.length > 1) {
      return visitor.visitUnionScalar(scalarTypes);
    } else {