Add constructors.

src/lib.rs

@@ -44,6 +44,14 @@ impl DiagnosticLevel {
     }
 }
 
+#[pymethods]
+impl DiagnosticLevel {
+    #[new]
+    pub fn new() -> Self {
+        Self::UNSET
+    }
+}
+
 #[pyclass]
 pub struct DiagnosticStatus {
     #[pyo3(get, set)]
@@ -58,6 +66,20 @@ pub struct DiagnosticStatus {
     values: Py<PyDict>,
 }
 
+#[pymethods]
+impl DiagnosticStatus {
+    #[new]
+    pub fn new(py: Python<'_>) -> Self {
+        Self {
+            level: DiagnosticLevel::new(),
+            name: PyString::new(py, "").unbind(),
+            message: PyString::new(py, "").unbind(),
+            hardware_id: PyString::new(py, "").unbind(),
+            values: PyDict::new(py).unbind(),
+        }
+    }
+}
+
 impl DiagnosticStatus {
     fn from_rust<'py>(
         py: Python<'py>,