232: sytle can be blank (#233)

* style can be blank

Python/dawgie/__init__.py

@@ -872,6 +872,8 @@ def features(self)->[Feature]: raise NotImplementedError()
 class Visitor:
     def add_declaration (self, text:str, **kwds)->None:
         raise NotImplementedError()
+    def add_declaration_inline(self, text:str, **kwds)->None:
+        raise NotImplementedError()
     def add_image (self, alternate:str, label:str, img:bytes)->None:
         raise NotImplementedError()
     def add_primitive (self, value, label:str=None)->None:

Python/dawgie/de/html.py

@@ -182,6 +182,10 @@ def add_declaration(self, text: str, **kwds) -> None:
         return
 
     def add_declaration_inline(self, text: str, **kwds) -> None:
+        # have to walk through a bunch of possiblities of input meaning that
+        # this function is basically a horde of branches. Therefore asking
+        # pylint: disable=too-many-branches
+        #
         # attributes that apply to presentation
         # class allows application of predefined css within preloaded
         #     stylesheets files -- if file isn't preloaded there is no effect
@@ -192,9 +196,11 @@ def add_declaration_inline(self, text: str, **kwds) -> None:
         # escape double-quotes only, allow single-quotations for css
         # html.escape() rules out certain advanced constructs but they can
         # be inserted via a stylesheet
-        attrib_value = html.escape(str(kwds['style']),
-                                   quote=False).replace("\"", """)
-        style = f" style=\"{attrib_value}\" " if 'style' in kwds else ""
+        if 'style' in kwds:
+            attrib_value = html.escape(str(kwds['style']),
+                                       quote=False).replace("\"", """)
+            style = f" style=\"{attrib_value}\" "
+        else: style = ""
 
         # tags for configuration settings (e.g. __<custom_name> in class vars)
         # -- embed external files before inline scripts --