Refactor to use new getter

Avoids directory list calls
we do lose the valid name thing but I think at this point that will have to be something else. e.g. a tutorial where we call `print(project.directory.get_directory_list())`

Author: anthony-chaudhary

sdk/diffgram/core/core.py

@@ -296,29 +296,8 @@ def set_directory_by_name(self, name):
 
         """
 
-        if name is None:
-            raise Exception("No name provided.")
-
-        # Don't refresh by default, just set from existing
-
-        names_attempted = []
-        did_set = False
-
-        if not self.directory_list:
-            self.directory_list = self.directory.get_directory_list()
-
-        for directory in self.directory_list:
-
-            if directory.nickname == name:
-                self.set_default_directory(directory = directory)
-                did_set = True
-                break
-            else:
-                names_attempted.append(directory.nickname)
-
-        if did_set is False:
-            raise Exception(name, " does not exist. Valid names are: " +
-                            str(names_attempted))
+        directory = self.directory.get(name = name)
+        self.set_default_directory(directory = directory)
 
 
     def set_default_directory(self,