Error on running aws_regions initialization error

[kabads]

Response:
{
  "errorMessage": "module initialization error"
}

Request ID:
"c04a9e8e-5e6a-11e8-8d00-0fbf7811aa04"

Function Logs:
START RequestId: c04a9e8e-5e6a-11e8-8d00-0fbf7811aa04 Version: $LATEST
module initialization error: 'aws_regions'

END RequestId: c04a9e8e-5e6a-11e8-8d00-0fbf7811aa04
REPORT RequestId: c04a9e8e-5e6a-11e8-8d00-0fbf7811aa04	Duration: 164.95 ms	Billed Duration: 200 ms 	Memory Size: 192 MB	Max Memory Used: 25 MB	
module initialization error
'aws_regions'

[kabads]

Could your blog detail how to find out the aws_regions environment variable? Thanks.