Remove get_css_style since replacey by CssStyle

We now use CssStyle to embedd it into the widgets.

src/scwidgets/__init__.py

@@ -1,7 +1,7 @@
 __version__ = "0.1.0-dev0"
 __authors__ = "the scicode-widgets developer team"
 
-from ._css_style import CssStyle, get_css_style
+from ._css_style import CssStyle 
 from .check import *  # noqa: F403
 from .code import *  # noqa: F403
 from .cue import *  # noqa: F403
@@ -10,7 +10,6 @@
 __all__ = [  # noqa: F405
     # css_style
     "CssStyle",
-    "get_css_style",
     # cue
     "CueWidget",
     "CheckCueBox",

src/scwidgets/_css_style.py

@@ -15,10 +15,3 @@ def __init__(self, preamble: str = ""):
             style_txt = file.read()
 
         HTML.__init__(self, preamble + "<style>" + style_txt + "</style>")
-
-
-def get_css_style() -> HTML:
-    return CssStyle(
-        preamble="HTML with scicode-widget css style sheet. "
-        "Please keep this cell output alive."
-    )

tests/__init__.py

@@ -1,4 +1,5 @@
 from scwidgets import (  # noqa: F401
+    CssStyle,
     AssertResult,
     Check,
     CheckableWidget,