XML generation with Kotlin extension functions

AppExtensionFuncs.kt

//  XML generation by code
//  based on https://www.schibsted.pl/blog/back-end/readable-xml-kotlin-extensions/
fun XmlSerializer.document(docName: String = "UTF-8",
                           xmlStringWriter: StringWriter = StringWriter(),
                           init: XmlSerializer.() -> Unit): String {
    startDocument(docName, true)
    xmlStringWriter.buffer.setLength(0) //  refreshing string writer due to reuse
    setOutput(xmlStringWriter)
    init()
    endDocument()
    return xmlStringWriter.toString()
}

//  element
fun XmlSerializer.element(name: String, init: XmlSerializer.() -> Unit) {
    startTag("", name)
    init()
    endTag("", name)
}

//  element with attribute & content
fun XmlSerializer.element(name: String,
                          content: String,
                          init: XmlSerializer.() -> Unit) {
    startTag("", name)
    init()
    text(content)
    endTag("", name)
}

//  element with content
fun XmlSerializer.element(name: String, content: String) =
        element(name) {
            text(content)
        }

fun XmlSerializer.attribute(name: String, value: String) =
        attribute("", name, value)

DashBoardActivity.kt

class DashBoardActivity : AppCompatActivity() {
  
    @Inject
    lateinit var xmlSerializer: XmlSerializer // val xmlSerializer = Xml.newSerializer()
    
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        makingXML()
    }

    private fun makingXML() {
        val USD: Currency = Currency.getInstance("USD")
        val EUR: Currency = Currency.getInstance("EUR")

        val persons = listOf(
                Person(Name("John", "Doe"),
                        listOf(
                                Account("JP Morgan Chase & Co", "000-111-222-333", USD),
                                Account("Goldman Sachs", "000-999999999-222-444", EUR)
                        )
                ),
                Person(Name("Jane", "Doe"),
                        listOf(
                                Account("JP Morgan Chase & Co", "000-777-222-333", USD),
                                Account("Goldman Sachs", "000-888888888-222-444", EUR)))
        )

        val thisIsXML = xmlSerializer.document {
            element("persons") {
                attribute("version", "1.1")
                attribute("created", Calendar.getInstance().time.toString())
                persons.forEach { (name, accounts) ->
                    element("person") {
                        element("name") {
                            element("first", name.first)
                            element("last", name.last)
                        }
                        element("accounts") {
                            accounts.forEach { (bank, number, currency) ->
                                element("account") {
                                    element("bank", bank)
                                    element("number", number)
                                    element("currency", currency.currencyCode)
                                }
                            }
                        }
                    }
                }
            }
        }
        println(thisIsXML) // refer output1
      
      thisIsXML = xmlSerializer.document {
            element("Movies") {
                element("row") {
                    attribute("no", "1")
                    element("FL", "6000000066015") {
                        attribute("val", "TicketId")
                    }
                    element("FL", "Dunkirk") {
                        attribute("val", "MovieName")
                    }
                    element("FL") {
                        attribute("val", "TimeLog")
                        element("row") {
                            attribute("no", "1")
                            element("FL", "23/01/2018") {
                                attribute("val", "logDate")
                            }
                            element("FL", "08:00") {
                                attribute("val", "startTime")
                            }
                        }
                    }
                }
            }
        }
      println(thisIsXML) // refer output2
    }
}

model.kt

data class Name(
        val first: String,
        val last: String
)

data class Account(
        val bank: String, 
        val number: String, 
        val currency: Currency
)

data class Person(
        val name: Name, 
        val accounts: List<Account>
)

output1

<?xml version="1.0" encoding="UTF-8"?>
<persons version="1.1" created="Mon Jan 22 19:15:38 GMT+05:30 2018">
   <person>
      <name>
         <first>John</first>
         <last>Doe</last>
      </name>
      <accounts>
         <account>
            <bank>JP Morgan Chase &amp; Co</bank>
            <number>000-111-222-333</number>
            <currency>USD</currency>
         </account>
         <account>
            <bank>Goldman Sachs</bank>
            <number>000-999999999-222-444</number>
            <currency>EUR</currency>
         </account>
      </accounts>
   </person>
   <person>
      <name>
         <first>Jane</first>
         <last>Doe</last>
      </name>
      <accounts>
         <account>
            <bank>JP Morgan Chase &amp; Co</bank>
            <number>000-777-222-333</number>
            <currency>USD</currency>
         </account>
         <account>
            <bank>Goldman Sachs</bank>
            <number>000-888888888-222-444</number>
            <currency>EUR</currency>
         </account>
      </accounts>
   </person>
</persons>

output2

<?xml version="1.0" encoding="UTF-8"?>
<Movies>
   <row no="1">
      <FL val="TicketId">6000000066015</FL>
      <FL val="MovieName">Dunkirk</FL>
      <FL val="TimeLog">
         <row no="1">
            <FL val="date">23/01/2018</FL>
            <FL val="startTime">08:00</FL>
         </row>
      </FL>
   </row>
</Movies>

How to printout XmlSerializer to view in console log?