I am currently receiving 400 errors when invoking the `list_builds()` method (seen here: <https://googleapis.dev/python/cloudbuild/latest/gapic/v1/api.html?highlight=list_builds#google.cloud.devtools.cloudbuild_v1.CloudBuildClient.list_builds>)

The following command works using gcloud:

`gcloud builds list --filter="status=FAILURE"`

However, the following API call returns `google.api_core.exceptions.InvalidArgument: 400 Error processing filter expression`

```
for element in client.list_builds("REDACTED", filter_="status=FAILURE"):
    # process element
    pass

```

I'm guessing I'm missing something very obvious and simple here but I can't exactly figure out what I'm doing wrong