Using the filter method with Kotlin

Question

I have the class Posicao and in it I have an attribute data: LocalDate.

I have an Array of FaixaPreco which contains 12 objects, 1 for each month of the year.

Based on the position date, I wanted to retrieve the FaixaPreco which fits:

It may be so, dataPosicao >= dataInicial of range.

data class Posicao(
    val id: Long? = null,
    var data: LocalDate? = null,
    var nome: String? = null
)

data class FaixaPreco(
    val id: Long? = null,
    var dataInicial: LocalDate,
    var taxaAa: BigDecimal? = null
)

val posicao = Posicao(1L, LocalDate.of(2021, 1, 13), "posição")
    
    
val faixas: MutableList<FaixaPreco> = mutableListOf();
faixas.add(FaixaPreco(1L, LocalDate.of(2021, 1, 12), BigDecimal("0.01")))
faixas.add(FaixaPreco(2L, LocalDate.of(2021, 2, 12), BigDecimal("0.03")))
faixas.add(FaixaPreco(3L, LocalDate.of(2021, 3, 12), BigDecimal("0.05")))
    
val faixaPreco = faixas.firstOrNull { posicao.data!!.isAfter(it.dataInicial) }