How to use the ngx-custom-validators.CustomValidators.lt function in ngx-custom-validators

func: CustomValidators.equalTo,
      params: ["equalTo"]
    },
    gt: {
      func: CustomValidators.gt,
      params: ["gt"]
    },
    gte: {
      func: CustomValidators.gte,
      params: ["gte"]
    },
    json: {
      func: CustomValidators.json
    },
    lt: {
      func: CustomValidators.lt,
      params: ["lt"]
    },
    lte: {
      func: CustomValidators.lte,
      params: ["lte"]
    },
    maxDate: {
      func: CustomValidators.maxDate,
      params: ["maxDate"]
    },
    minDate: {
      func: CustomValidators.minDate,
      params: ["minDate"]
    },
    notEqual: {
      func: CustomValidators.notEqual,