diff --git a/homeassistant/util/ruamel_yaml.py b/homeassistant/util/ruamel_yaml.py
index 0659e3d8054..ffdc4bf6b84 100644
--- a/homeassistant/util/ruamel_yaml.py
+++ b/homeassistant/util/ruamel_yaml.py
@@ -3,7 +3,7 @@ import logging
 import os
 from os import O_CREAT, O_TRUNC, O_WRONLY, stat_result
 from collections import OrderedDict
-from typing import Union, List, Dict
+from typing import Union, List, Dict, Optional
 
 import ruamel.yaml
 from ruamel.yaml import YAML
@@ -22,6 +22,8 @@ JSON_TYPE = Union[List, Dict, str]  # pylint: disable=invalid-name
 class ExtSafeConstructor(SafeConstructor):
     """Extended SafeConstructor."""
 
+    name = None  # type: Optional[str]
+
 
 class UnsupportedYamlError(HomeAssistantError):
     """Unsupported YAML."""
@@ -31,22 +33,25 @@ class WriteError(HomeAssistantError):
     """Error writing the data."""
 
 
-def _include_yaml(constructor: SafeConstructor, node: ruamel.yaml.nodes.Node) \
-        -> JSON_TYPE:
+def _include_yaml(constructor: ExtSafeConstructor,
+                  node: ruamel.yaml.nodes.Node) -> JSON_TYPE:
     """Load another YAML file and embeds it using the !include tag.
 
     Example:
         device_tracker: !include device_tracker.yaml
     """
+    if constructor.name is None:
+        raise HomeAssistantError(
+            "YAML include error: filename not set for %s" % node.value)
     fname = os.path.join(os.path.dirname(constructor.name), node.value)
     return load_yaml(fname, False)
 
 
-def _yaml_unsupported(constructor: SafeConstructor, node:
+def _yaml_unsupported(constructor: ExtSafeConstructor, node:
                       ruamel.yaml.nodes.Node) -> None:
     raise UnsupportedYamlError(
         'Unsupported YAML, you can not use {} in {}'
-        .format(node.tag, os.path.basename(constructor.name)))
+        .format(node.tag, os.path.basename(constructor.name or '(None)')))
 
 
 def object_to_yaml(data: JSON_TYPE) -> str:
@@ -80,7 +85,7 @@ def load_yaml(fname: str, round_trip: bool = False) -> JSON_TYPE:
         yaml = YAML(typ='rt')
         yaml.preserve_quotes = True
     else:
-        if not hasattr(ExtSafeConstructor, 'name'):
+        if ExtSafeConstructor.name is None:
             ExtSafeConstructor.name = fname
         yaml = YAML(typ='safe')
         yaml.Constructor = ExtSafeConstructor