1 files changed, 14 insertions, 0 deletions
diff --git a/lib/sqlalchemy/ext/asyncio/exc.py b/lib/sqlalchemy/ext/asyncio/exc.py
new file mode 100644
index 000000000..6137bf6df
--- /dev/null
+++ b/lib/sqlalchemy/ext/asyncio/exc.py
@@ -0,0 +1,14 @@
+from ... import exc
+
+
+class AsyncMethodRequired(exc.InvalidRequestError):
+    """an API can't be used because its result would not be
+    compatible with async"""
+
+
+class AsyncContextNotStarted(exc.InvalidRequestError):
+    """a startable context manager has not been started."""
+
+
+class AsyncContextAlreadyStarted(exc.InvalidRequestError):
+    """a startable context manager is already started."""