Fix wrong escape sequences

Following warnings shows up all over the code:
```
 SyntaxWarning: invalid escape sequence ...
```
Let's fix it.

Author: dkropachev

cassandra/cqlengine/connection.py

@@ -316,14 +316,14 @@ def setup(
         retry_connect=False,
         **kwargs):
     """
-    Setup a the driver connection used by the mapper
+    Setup the driver connection used by the mapper
 
     :param list hosts: list of hosts, (``contact_points`` for :class:`cassandra.cluster.Cluster`)
     :param str default_keyspace: The default keyspace to use
     :param int consistency: The global default :class:`~.ConsistencyLevel` - default is the same as :attr:`.Session.default_consistency_level`
     :param bool lazy_connect: True if should not connect until first use
     :param bool retry_connect: True if we should retry to connect even if there was a connection failure initially
-    :param \*\*kwargs: Pass-through keyword arguments for :class:`cassandra.cluster.Cluster`
+    :param kwargs: Pass-through keyword arguments for :class:`cassandra.cluster.Cluster`
     """
 
     from cassandra.cqlengine import models

cassandra/cqlengine/query.py

@@ -205,8 +205,8 @@ def add_callback(self, fn, *args, **kwargs):
 
         :param fn: Callable object
         :type fn: callable
-        :param \*args: Positional arguments to be passed to the callback at the time of execution
-        :param \*\*kwargs: Named arguments to be passed to the callback at the time of execution
+        :param args: Positional arguments to be passed to the callback at the time of execution
+        :param kwargs: Named arguments to be passed to the callback at the time of execution
         """
         if not callable(fn):
             raise ValueError("Value for argument 'fn' is {0} and is not a callable object.".format(type(fn)))
@@ -276,8 +276,8 @@ class ContextQuery(object):
     A Context manager to allow a Model to switch context easily. Presently, the context only
     specifies a keyspace for model IO.
 
-    :param \*args: One or more models. A model should be a class type, not an instance.
-    :param \*\*kwargs: (optional) Context parameters: can be *keyspace* or *connection*
+    :param args: One or more models. A model should be a class type, not an instance.
+    :param kwargs: (optional) Context parameters: can be *keyspace* or *connection*
 
     For example:
 

tests/integration/standard/test_cluster.py

@@ -150,7 +150,7 @@ def test_raise_error_on_control_connection_timeout(self):
         get_node(1).pause()
         cluster = TestCluster(contact_points=['127.0.0.1'], connect_timeout=1)
 
-        with self.assertRaisesRegex(NoHostAvailable, "OperationTimedOut\('errors=Timed out creating connection \(1 seconds\)"):
+        with self.assertRaisesRegex(NoHostAvailable, r"OperationTimedOut\('errors=Timed out creating connection \(1 seconds\)"):
             cluster.connect()
         cluster.shutdown()
 

tests/integration/standard/test_metadata.py

@@ -1677,7 +1677,7 @@ def test_function_no_parameters(self):
 
         with self.VerifiedFunction(self, **kwargs) as vf:
             fn_meta = self.keyspace_function_meta[vf.signature]
-            self.assertRegex(fn_meta.as_cql_query(), "CREATE FUNCTION.*%s\(\) .*" % kwargs['name'])
+            self.assertRegex(fn_meta.as_cql_query(), r'CREATE FUNCTION.*%s\(\) .*' % kwargs['name'])
 
     def test_functions_follow_keyspace_alter(self):
         """
@@ -1725,12 +1725,12 @@ def test_function_cql_called_on_null(self):
         kwargs['called_on_null_input'] = True
         with self.VerifiedFunction(self, **kwargs) as vf:
             fn_meta = self.keyspace_function_meta[vf.signature]
-            self.assertRegex(fn_meta.as_cql_query(), "CREATE FUNCTION.*\) CALLED ON NULL INPUT RETURNS .*")
+            self.assertRegex(fn_meta.as_cql_query(), r'CREATE FUNCTION.*\) CALLED ON NULL INPUT RETURNS .*')
 
         kwargs['called_on_null_input'] = False
         with self.VerifiedFunction(self, **kwargs) as vf:
             fn_meta = self.keyspace_function_meta[vf.signature]
-            self.assertRegex(fn_meta.as_cql_query(), "CREATE FUNCTION.*\) RETURNS NULL ON NULL INPUT RETURNS .*")
+            self.assertRegex(fn_meta.as_cql_query(), r'CREATE FUNCTION.*\) RETURNS NULL ON NULL INPUT RETURNS .*')
 
 
 @requires_java_udf

tests/integration/standard/test_query.py

@@ -167,7 +167,7 @@ def test_client_ip_in_trace(self):
         client_ip = trace.client
 
         # Ip address should be in the local_host range
-        pat = re.compile("127.0.0.\d{1,3}")
+        pat = re.compile(r'127.0.0.\d{1,3}')
 
         # Ensure that ip is set
         self.assertIsNotNone(client_ip, "Client IP was not set in trace with C* >= 2.2")