<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_compute_credentials(key):
 """Authenticates a service account for the compute engine. This uses the `oauth2client.service_account` module. Since the `google` Python package does not support the compute engine (yet?), we need to make direct HTTP requests. For that we need authentication tokens. Obtaining these based on the credentials provided by the `google.auth2` module is much more cumbersome than using the `oauth2client` module. See: - https://cloud.google.com/iap/docs/authentication-howto - https://developers.google.com/identity/protocols/OAuth2ServiceAccount TODO: docstring"""

    scopes = ['https://www.googleapis.com/auth/compute']

    credentials = ServiceAccountCredentials.from_json_keyfile_dict(
        key, scopes=scopes)
    
    return credentials