diff --git a/src/wireviz/wv_dataclasses.py b/src/wireviz/wv_dataclasses.py
index 2b5ef87c..3081ae49 100644
--- a/src/wireviz/wv_dataclasses.py
+++ b/src/wireviz/wv_dataclasses.py
@@ -747,7 +747,7 @@ def __post_init__(self) -> None:
         if self.show_name is None:
             self.show_name = not self.is_autogenerated
 
-        if not self.show_wirenumbers:
+        if self.show_wirenumbers is None:
             # by default, show wire numbers for cables, hide for bundles
             self.show_wirenumbers = self.category != "bundle"
 
diff --git a/src/wireviz/wv_utils.py b/src/wireviz/wv_utils.py
index a2bff03f..58209e12 100644
--- a/src/wireviz/wv_utils.py
+++ b/src/wireviz/wv_utils.py
@@ -70,9 +70,10 @@ def expand(yaml_data):
 
 
 def get_single_key_and_value(d: dict):
-    k = list(d.keys())[0]
-    v = d[k]
-    return (k, v)
+    # used for defining a line in a harness' connection set
+    # E.g. for the YAML input `- X1: 1`
+    # this function returns a tuple in the form ("X1", "1")
+    return next(iter(d.items()))
 
 
 def int2tuple(inp):