# swegym / getmoto__moto-7336

- taskset: [swegym](https://harnessreport.com/tasks/swegym.md)
- difficulty: hard
- category: debugging
- language: 
- runnable from the site: no
- agent timeout: 3000s

## Results by harness

_none yet_

## Instruction

```
Default IAM user is not support in AWS China. user/moto
I have a code like that, 
```
def assume_cross_account_role_via_arn(role_arn, role_session_name=None, region_name=None) -> boto3.Session:
    _session = boto3.Session(region_name=region_name)
    session = assume_role(_session, role_arn, RoleSessionName=role_session_name, region_name=region_name)
    logger.info("Role: %s has been successfully assumed.", role_arn)
    return session
```
When I use assume_role() in AWS China , the moto default user is `arn:aws:sts::123456789012:user/moto`. So it can not be assumed because of the different partition(aws-cn).

And I have seen the code in https://github.com/getmoto/moto/blob/d98972ffc8c0cf67f7572478b722b0b59a446479/moto/sts/models.py#L189 

```
    def get_caller_identity(self, access_key_id: str) -> Tuple[str, str, str]:
        assumed_role = self.get_assumed_role_from_access_key(access_key_id)
        if assumed_role:
            return assumed_role.user_id, assumed_role.arn, assumed_role.account_id

        iam_backend = iam_backends[self.account_id]["global"]
        user = iam_backend.get_user_from_access_key_id(access_key_id)
        if user:
            return user.id, user.arn, user.account_id

        # Default values in case the request does not use valid credentials generated by moto
        user_id = "AKIAIOSFODNN7EXAMPLE"
        arn = f"arn:aws:sts::{self.account_id}:user/moto"
        return user_id, arn, self.account_id
```
It's hard code. Maybe it's better to use the var in partition.
```
    partition = boto3.Session().get_partition_for_region(region_name=region)
    arn = f"arn:{partition}:sts::{self.account_id}:user/moto"
```

By the way, how can I generate a new user to replace the default moto user ?

Thank you ~
```
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