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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_role_arn(role_name, env, region):
 """Get role ARN given role name. Args: role_name (str):
 Role name to lookup env (str):
 Environment in which to lookup region (str):
 Region Returns: ARN if role found """

    session = boto3.Session(profile_name=env, region_name=region)
    iam_client = session.client('iam')

    LOG.debug('Searching for %s.', role_name)

    role = iam_client.get_role(RoleName=role_name)
    role_arn = role['Role']['Arn']

    LOG.debug("Found role's %s ARN %s", role_name, role_arn)

    return role_arn