Added errors.lookup() function

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/errors.py b/lib/errors.py
index dbf829b..492d5aa 100644
--- a/lib/errors.py
+++ b/lib/errors.py
@@ -10,6 +10,14 @@ from psycopg2._psycopg import (
     QueryCanceledError, TransactionRollbackError)
 
 
+def lookup(code):
+    """Lookup an error code and return its exception class.
+
+    Raise `!KeyError` if the code is not found.
+    """
+    return _by_sqlstate[code]
+
+
 _by_sqlstate = {}