steps/ast-builders/schema-imports.js
function importSpecifier(name, def) {
    return {
        type: def === true ? 'ImportDefaultSpecifier' : 'ImportSpecifier',
        id: {
            type: 'Identifier',
            name: name
        },
        name: null
    };
}
function importSpecifier(name, def) {
    return {
        type: def === true ? 'ImportDefaultSpecifier' : 'ImportSpecifier',
        id: {
            type: 'Identifier',
            name: name
        },
        name: null
    };
}
Couldn't figure out b.importSpecifier