AssumeRoleTokenProviderNotSetError when using MFA

[dtlhlbs]

We have MFA enabled so I have configured my AWS profile like:

[profile dev]
source_profile=default
role_arn=arn:aws:iam::987654321:role/MyRole
mfa_serial = arn:aws:iam::123456789:mfa/MyUser

When I run aws lightsail push-container-image --region ap-southeast-2 --service-name docs --label latest --image myorg/docs under this profile I get an error:

AssumeRoleTokenProviderNotSetError: assume role with MFA enabled, but AssumeRoleTokenProvider session option not set.
Command '['lightsailctl', '--plugin', '--input-stdin']' returned non-zero exit status 1.

[dtlhlbs]

Have resolved as per instructions at https://repost.aws/questions/QUacz36ED4S9OOFSAlwmbIvg/push-a-container-to-lightsail-with-assume-role-and-mfa after reading hints at aws/amazon-ecs-cli#284