diff --git a/freqtrade/constants.py b/freqtrade/constants.py
index ffcd87744..de1e7aa51 100644
--- a/freqtrade/constants.py
+++ b/freqtrade/constants.py
@@ -112,6 +112,8 @@ MINIMAL_CONFIG = {
     }
 }
 
+__MESSAGE_TYPE_DICT: Dict[str, Dict[str, str]] = {x: {'type': 'object'} for x in RPCMessageType}
+
 # Required json-schema for user specified config
 CONF_SCHEMA = {
     'type': 'object',
@@ -354,7 +356,8 @@ CONF_SCHEMA = {
                 'format': {'type': 'string', 'enum': WEBHOOK_FORMAT_OPTIONS, 'default': 'form'},
                 'retries': {'type': 'integer', 'minimum': 0},
                 'retry_delay': {'type': 'number', 'minimum': 0},
-                **dict([(x, {'type': 'object'}) for x in RPCMessageType]),
+                **__MESSAGE_TYPE_DICT,
+                # **{x: {'type': 'object'} for x in RPCMessageType},
                 # Below -> Deprecated
                 'webhookentry': {'type': 'object'},
                 'webhookentrycancel': {'type': 'object'},
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 6c8cf8fcc..ca9b675ec 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -8,7 +8,7 @@
 
 coveralls==3.3.1
 ruff==0.0.272
-mypy==1.3.0
+mypy==1.4.1
 pre-commit==3.3.3
 pytest==7.4.0
 pytest-asyncio==0.21.0