Fixing flake8 errors

Author: Golf Player

nbclient/client.py

@@ -240,7 +240,7 @@ class NotebookClient(LoggingConfigurable):
         allow_none=True,
         help=dedent(
             """
-            A callable which executes after a cell execution is complete. It is 
+            A callable which executes after a cell execution is complete. It is
             called even when a cell results in a failure.
             """
         ),
@@ -699,7 +699,7 @@ def _check_raise_for_error(self, cell, cell_index, exec_reply):
         if (exec_reply is not None) and exec_reply['content']['status'] == 'error':
             run_hook(self.on_cell_error, cell, cell_index)
             if self.force_raise_errors or not cell_allows_errors:
-                    raise CellExecutionError.from_cell_and_msg(cell, exec_reply['content'])
+                raise CellExecutionError.from_cell_and_msg(cell, exec_reply['content'])
 
     async def async_execute_cell(self, cell, cell_index, execution_count=None, store_history=True):
         """