function classes () {
  return this.$formulate.classes({
    ...this.$props,
    ...this.pseudoProps,
    ...{
      attrs: this.filteredAttributes,
      classification: this.classification,
      hasErrors: this.hasVisibleErrors,
      hasValue: this.hasValue,
      helpPosition: this.logicalHelpPosition,
      isValid: this.isValid,
      labelPosition: this.logicalLabelPosition,
      type: this.type,
      value: this.proxy
    }
  })
}
Apply the result of the classes computed prop to any existing prop classes.