Please new flake8 (#2789)

it stopped liking lack of space character between `,` and `\`
```python
foo,\
    bar
```

features/environment.py

@@ -59,7 +59,7 @@ class AbstractController(abc.ABC):
                 break
             time.sleep(1)
         else:
-            assert False,\
+            assert False, \
                 "{0} instance is not available for queries after {1} seconds".format(self._name, max_wait_limit)
 
     def stop(self, kill=False, timeout=15, _=False):

features/steps/basic_replication.py

@@ -21,7 +21,7 @@ def start_duplicate_patroni(context, name, port):
         context.pctl.start('dup-' + name, custom_config=config)
         assert False, "Process was expected to fail"
     except AssertionError as e:
-        assert 'is not running after being started' in str(e),\
+        assert 'is not running after being started' in str(e), \
             "No error was raised by duplicate start of {0} ".format(name)
 
 
@@ -88,14 +88,14 @@ def table_is_present_on(context, table_name, pg_name, max_replication_delay):
             break
         sleep(1)
     else:
-        assert False,\
+        assert False, \
             "Table {0} is not present on {1} after {2} seconds".format(table_name, pg_name, max_replication_delay)
 
 
 @then('{pg_name:w} role is the {pg_role:w} after {max_promotion_timeout:d} seconds')
 def check_role(context, pg_name, pg_role, max_promotion_timeout):
     max_promotion_timeout *= context.timeout_multiplier
-    assert context.pctl.check_role_has_changed_to(pg_name, pg_role, timeout=int(max_promotion_timeout)),\
+    assert context.pctl.check_role_has_changed_to(pg_name, pg_role, timeout=int(max_promotion_timeout)), \
         "{0} role didn't change to {1} after {2} seconds".format(pg_name, pg_role, max_promotion_timeout)
 
 
@@ -111,5 +111,5 @@ def replication_works(context, primary, replica, time_limit):
 @then('there is a "{message}" {level:w} in the {node} patroni log')
 def check_patroni_log(context, message, level, node):
     messsages_of_level = context.pctl.read_patroni_log(node, level)
-    assert any(message in line for line in messsages_of_level),\
+    assert any(message in line for line in messsages_of_level), \
         "There was no {0} {1} in the {2} patroni log".format(message, level, node)

features/steps/citus.py

@@ -125,5 +125,5 @@ def check_transaction(context, name):
 
 @step("a transaction finishes in {timeout:d} seconds")
 def check_transaction_timeout(context, timeout):
-    assert (datetime.now(tzutc) - context.xact_start).seconds > timeout,\
+    assert (datetime.now(tzutc) - context.xact_start).seconds > timeout, \
         "a transaction finished earlier than in {0} seconds".format(timeout)

features/steps/patroni_api.py

@@ -98,7 +98,7 @@ def do_run(context, cmd):
 @then('I receive a response {component:w} {data}')
 def check_response(context, component, data):
     if component == 'code':
-        assert context.status_code == int(data),\
+        assert context.status_code == int(data), \
             "status code {0} != {1}, response: {2}".format(context.status_code, data, context.response)
     elif component == 'returncode':
         assert context.status_code == int(data), "return code {0} != {1}, {2}".format(context.status_code,
@@ -158,7 +158,7 @@ def check_http_response(context, url, value, timeout, negate=False):
             break
         time.sleep(1)
     else:
-        assert False,\
+        assert False, \
             "Value {0} is {1} present in response after {2} seconds".format(value, "not" if not negate else "", timeout)