Terraform variable error : The given value is not valid - google-cloud-platform

Question

I am trying to create a monitoring alert policy using terraform. But in the plan stage i am getting the below error on the variable. Has anyone faced a similar issue in the past ? I am new to terraform and i can trying to create a iterable resource for monitoring alert policy in gcp.
Error: Invalid value for input variable
│
│ on terraform.tfvars line 149:
│ 149: alert_policies = {
│ 150: "composer_alert" = {
│ 151: combiner = "OR"
│ 152: display_name = "Alert Strategy"
│ 153: enabled = "true"
│ 154: conditions = [
│ 155: {display_name = "Bytes used condition"
│ 156: conditions_threshold = {
│ 157: "1" = {
│ 158: comparison = "COMPARISON_GT"
│ 159: duration = "0s"
│ 160: filter = "resource.type = \"cloud_composer_environment\" AND resource.labels.project_id = \"prj-comp-01\" AND metric.type = \"composer.googleapis.com/environment/database/disk/bytes_used\""
│ 161: threshold_value = 1600000000
│ 162: alignment_period = "300s"
│ 163: cross_series_reducer = "REDUCE_NONE"
│ 164: group_by_fields = ["project_id"]
│ 165: per_series_aligner = "ALIGN_MEAN"
│ 166: trigger_count = 1
│ 167: trigger_percent = 100
│ 168: }
│ 169: }
│ 170: }
│ 171: ]
│ 172: notification_channels = [
│ 173: "projects/prj-test-01/notificationChannels/2276385315451985010"
│ 174: ]
│ 175: }
│ 176: }
│
│ The given value is not valid for variable "alert_policies": a number is
│ required.
╵
╷
│ Error: Incorrect variable type
│
│ on variables.tf line 392:
│ 392: variable "alert_policies" {
│
│ The resolved value of variable "alert_policies" is not appropriate: a
│ number is required.
Variables.tf****
variable "alert_policies" {
type = map(object({
combiner = optional(string)
display_name = optional(string)
enabled = optional(bool)
uptime_checks = optional(map(object({
duration = number
uptime_check_name = string
ssl_expiry_checks = optional(list(object({
days_left = number
})))
})))
conditions = list(object({
display_name = string
conditions_threshold = map(object({
comparison = string
duration = number
filter = string
threshold_value = number
alignment_period = number
cross_series_reducer = string
group_by_fields = list(string)
per_series_aligner = string
trigger_count = number
trigger_percent = number
}))
notification_channels = optional(list(string))
}))
}))
}
╵