tidy up

Author: mmatera

mathics/builtin/files.py

@@ -4914,7 +4914,7 @@ def apply(self, context, evaluation):
         'Needs[context_String]'
         contextstr = context.get_string_value()
         if contextstr == "":
-            return Symbol("Null")
+            return SymbolNull
         if contextstr[0]=="`":
             curr_ctxt = evaluation.definitions.get_current_context()
             contextstr = curr_ctxt + contextstr[1:]
@@ -4936,7 +4936,7 @@ def apply(self, context, evaluation):
                                     Symbol('System`$Packages'), context)
         already_loaded = already_loaded.evaluate(evaluation).is_true()
         if already_loaded:
-           return Symbol('Null')
+           return SymbolNull
 
         result = Expression('Get', context).evaluate(evaluation)
 

mathics/core/definitions.py

@@ -395,8 +395,6 @@ def get_package_names(self) -> typing.List[str]:
         packages = [c.get_string_value() for c in packages.leaves]
         return packages
 
-
-    
         #return sorted({name.split("`")[0] for name in self.get_names()})
 
     def shorten_name(self, name_with_ctx) -> str: