Support display no docstring (#119)

The `WidgetCodeInput` now supports to display no docstring docstring. We now
support in scwidgets to pass `None` value when no docstring should be
displayed. Fixed some formatting error in docs.

docs/src/getting_started.ipynb

@@ -89,7 +89,7 @@
     "    update=update_func,\n",
     "    update_mode=\"continuous\",\n",
     "    title=\"Sinus function\",\n",
-    "    description=\"Implements $\\sin(x\\omega)$\",\n",
+    "    description=\"Implements $\\\\sin(x\\\\omega)$\",\n",
     ")\n",
     "\n",
     "code_ex.run_update() # For the demonstration we run the widget one time\n",

pyproject.toml

@@ -30,7 +30,7 @@ classifiers = [
 dependencies = [
   "ipywidgets>=8.0.0",
   "numpy<2.0.0",
-  "widget_code_input>=4.0.13",
+  "widget_code_input>=4.0.17",
   "matplotlib",
   "termcolor"
 ]

src/scwidgets/code/_widget_code_input.py

@@ -8,7 +8,7 @@
 import types
 import warnings
 from functools import wraps
-from typing import Any, List, Optional, Tuple
+from typing import Any, List, Optional, Tuple, Union
 
 from widget_code_input import WidgetCodeInput
 from widget_code_input.utils import (
@@ -71,7 +71,6 @@ def __init__(
         if function_name is None:
             raise ValueError("function_name must be given if no function is given.")
         function_parameters = "" if function_parameters is None else function_parameters
-        docstring = "\n" if docstring is None else docstring
         function_body = "" if function_body is None else function_body
         self._builtins = {} if builtins is None else builtins
         super().__init__(
@@ -152,9 +151,13 @@ def function_parameters_name(self) -> List[str]:
         return self.function_parameters.replace(",", "").split(" ")
 
     @staticmethod
-    def get_docstring(function: types.FunctionType) -> str:
+    def get_docstring(function: types.FunctionType) -> Union[str, None]:
         docstring = function.__doc__
-        return "" if docstring is None else textwrap.dedent(docstring)
+        return (
+            None
+            if docstring is None
+            else textwrap.dedent(docstring).strip('"""')  # noqa: B005
+        )
 
     @staticmethod
     def _get_function_source_and_def(

tests/test_code.py

@@ -79,6 +79,7 @@ def test_get_function_paramaters(self):
         assert CodeInput.get_function_parameters(self.mock_function_7) == "x, **kwargs"
 
     def test_get_docstring(self):
+        assert CodeInput.get_docstring(self.mock_function_0) is None
         assert (
             CodeInput.get_docstring(self.mock_function_1)
             == "\nThis is an example function.\nIt adds two numbers.\n"