Checkly terraform module issue

[sachinmane1983]

          prod-api = {
name      = "PROD API"
tags      = ["prod", "backend"]
activated = true
locations = [
  "eu-west-1",
  "eu-central-1",
  "eu-west-2",
  "eu-west-3",
  "eu-north-1",
]

use_global_alert_settings = true

api_check_defaults_url = "https://api.xxxx.co.xx/"

environment_variables = []

email_alert_channel_sub          = ""
slack_alert_channel_sub          = ""
pagerduty_alert_channel_sub      = ""
opsgenie_alert_channel_sub       = ""
grafana_oncall_alert_channel_sub = "grafana-oncall"

},

variable "check_groups" {
description = "Checkly groups to organise related checks"
type = map(object({
name = string
tags = list(string)
locations = list(string)
use_global_alert_settings = bool

api_check_defaults_url = string

environment_variable = list(object({}))

email_alert_channel_sub          = string
slack_alert_channel_sub          = string
pagerduty_alert_channel_sub      = string
opsgenie_alert_channel_sub       = string
grafana_oncall_alert_channel_sub = string

}))

default = {}
}

error
The given value is not suitable for var.check_groups declared at variables.tf:173,1-24: element "prod-api": attribute "environment_variable" is required.

Originally posted by @sachinmane1983 in #254 (comment)