diff --git a/pyproject_toml_builder.py b/pyproject_toml_builder.py
index 125f94c..081b94c 100644
--- a/pyproject_toml_builder.py
+++ b/pyproject_toml_builder.py
@@ -47,7 +47,16 @@
 
 
 class NoDotsDict(dict):
-    """A custom dictionary class that disallows keys with dots ('.')."""
+    """A custom dictionary class that disallows keys with dots ('.').
+
+    Dots have a special meaning in TOML, so a key like `[a.b.c]` in a
+    `dict` would be dict["a"]["b"]["c"] but NOT dict["a.b.c"]. To avoid
+    this pitfall, we can disallow dots all together.
+
+    There are situations where a dotted key could be useful, like
+    `["127.0.0.1"] = "value"`. In this case, this the dict key is "127.0.0.1"
+    (and is not a nesting of subdicts).
+    """
 
     def __setitem__(self, key, value):
         if "." in key:
diff --git a/tests/test_pyproject_toml_builder.py b/tests/test_pyproject_toml_builder.py
index 6ab4985..17f57a0 100644
--- a/tests/test_pyproject_toml_builder.py
+++ b/tests/test_pyproject_toml_builder.py
@@ -158,7 +158,12 @@ def assert_outputted_pyproject_toml(
     pyproject_toml_path: Path, expected: dict[str, Any]
 ) -> None:
     """Compare each's contents casted to a dict."""
-    pyproject_toml_builder.NoDotsDict(expected)  # test that we aren't using dots
+
+    # test that we aren't using dots
+    no_dots = pyproject_toml_builder.NoDotsDict()
+    for key, value in expected.items():
+        no_dots[key] = value
+
     print()
     print("EXPECTED TOML OUTPUT:")
     print(expected)