diff --git a/balsam/__init__.py b/balsam/__init__.py
index b43cf51a..7578e3df 100644
--- a/balsam/__init__.py
+++ b/balsam/__init__.py
@@ -1,4 +1,4 @@
 from balsam.util import config_root_logger
 
-__version__ = "0.7.0.a22"
+__version__ = "0.7.0.a23"
 config_root_logger()
diff --git a/balsam/_api/model.py b/balsam/_api/model.py
index 38ae2c48..b889fd18 100644
--- a/balsam/_api/model.py
+++ b/balsam/_api/model.py
@@ -186,7 +186,7 @@ def __repr__(self) -> str:
 
     def __str__(self) -> str:
         d = self.display_dict()
-        return yaml.dump(d, sort_keys=False, indent=4)
+        return str(yaml.dump(d, sort_keys=False, indent=4))
 
     def __eq__(self, other: Any) -> bool:
         if not isinstance(other, BalsamModel):
diff --git a/balsam/_api/models.py b/balsam/_api/models.py
index 3321a5d5..ac91f412 100644
--- a/balsam/_api/models.py
+++ b/balsam/_api/models.py
@@ -1,5 +1,5 @@
-# This file was auto-generated via /home/turam/miniconda3/bin/python balsam/schemas/api_generator.py
-# [git rev 7634992]
+# This file was auto-generated via /Users/turam/opt/miniconda3/bin/python balsam/schemas/api_generator.py
+# [git rev 5034973]
 # Do *not* make changes to the API by changing this file!
 
 import datetime
@@ -765,7 +765,7 @@ class BatchJob(balsam._api.bases.BatchJobBase):
     job_mode = Field[balsam.schemas.batchjob.JobMode]()
     optional_params = Field[typing.Dict[str, str]]()
     filter_tags = Field[typing.Dict[str, str]]()
-    partitions = Field[Optional[typing.Union[typing.List[balsam.schemas.batchjob.BatchJobPartition], None]]]()
+    partitions = Field[typing.Optional[typing.List[balsam.schemas.batchjob.BatchJobPartition]]]()
     site_id = Field[int]()
     project = Field[str]()
     queue = Field[str]()
@@ -786,7 +786,7 @@ def __init__(
         queue: str,
         optional_params: Optional[typing.Dict[str, str]] = None,
         filter_tags: Optional[typing.Dict[str, str]] = None,
-        partitions: Optional[typing.Union[typing.List[balsam.schemas.batchjob.BatchJobPartition], None]] = None,
+        partitions: Optional[typing.Optional[typing.List[balsam.schemas.batchjob.BatchJobPartition]]] = None,
         **kwargs: Any,
     ) -> None:
         """
@@ -918,7 +918,7 @@ def create(
         queue: str,
         optional_params: Optional[typing.Dict[str, str]] = None,
         filter_tags: Optional[typing.Dict[str, str]] = None,
-        partitions: Optional[typing.Union[typing.List[balsam.schemas.batchjob.BatchJobPartition], None]] = None,
+        partitions: Optional[typing.Optional[typing.List[balsam.schemas.batchjob.BatchJobPartition]]] = None,
     ) -> BatchJob:
         """
         Create a new BatchJob object and save it to the API in one step.
diff --git a/balsam/config/config.py b/balsam/config/config.py
index e4c8f066..3f460ff6 100644
--- a/balsam/config/config.py
+++ b/balsam/config/config.py
@@ -236,10 +236,12 @@ def save(self, path: Union[str, Path]) -> None:
             fp.write(self.dump_yaml())
 
     def dump_yaml(self) -> str:
-        return yaml.dump(
-            json.loads(self.json()),
-            sort_keys=False,
-            indent=4,
+        return str(
+            yaml.dump(
+                json.loads(self.json()),
+                sort_keys=False,
+                indent=4,
+            )
         )
 
     @classmethod