Cleanup - use is_boto3_error_(message|code) (ansible-collections#268)

* Reorder imports
* Make use of is_boto3_error_message
* Mass-migration over to is_boto3_error_code
* Remove unused imports
* unused vars in exception
* Improve consistency around catching BotoCoreError and ClientError
* Remove unused imports
* Remove unused 'PolicyError' from iam_policy_info
* Avoid catching botocore.exceptions.ClientError when we only want some error codes
* Import camel_dict_to_snake_dict/snake_dict_to_camel_dict from ansible.module_utils.common.dict_transformations

This commit was initially merged in https://github.com/ansible-collections/community.aws
See: ansible-collections@4cf52ef

plugins/modules/cloudwatchevent_rule.py

@@ -154,8 +154,10 @@
 except ImportError:
     pass  # handled by AnsibleAWSModule
 
+from ansible.module_utils.common.dict_transformations import camel_dict_to_snake_dict
+
 from ansible_collections.amazon.aws.plugins.module_utils.core import AnsibleAWSModule
-from ansible_collections.amazon.aws.plugins.module_utils.ec2 import camel_dict_to_snake_dict
+from ansible_collections.amazon.aws.plugins.module_utils.core import is_boto3_error_code
 
 
 class CloudWatchEventRule(object):
@@ -174,12 +176,9 @@ def describe(self):
         """Returns the existing details of the rule in AWS"""
         try:
             rule_info = self.client.describe_rule(Name=self.name)
-        except botocore.exceptions.ClientError as e:
-            error_code = e.response.get('Error', {}).get('Code')
-            if error_code == 'ResourceNotFoundException':
-                return {}
-            self.module.fail_json_aws(e, msg="Could not describe rule %s" % self.name)
-        except botocore.exceptions.BotoCoreError as e:
+        except is_boto3_error_code('ResourceNotFoundException'):
+            return {}
+        except (botocore.exceptions.BotoCoreError, botocore.exceptions.ClientError) as e:  # pylint: disable=duplicate-except
             self.module.fail_json_aws(e, msg="Could not describe rule %s" % self.name)
         return self._snakify(rule_info)
 
@@ -237,12 +236,9 @@ def list_targets(self):
         """Lists the existing targets for the rule in AWS"""
         try:
             targets = self.client.list_targets_by_rule(Rule=self.name)
-        except botocore.exceptions.ClientError as e:
-            error_code = e.response.get('Error', {}).get('Code')
-            if error_code == 'ResourceNotFoundException':
-                return []
-            self.module.fail_json_aws(e, msg="Could not find target for rule %s" % self.name)
-        except botocore.exceptions.BotoCoreError as e:
+        except is_boto3_error_code('ResourceNotFoundException'):
+            return []
+        except (botocore.exceptions.BotoCoreError, botocore.exceptions.ClientError) as e:  # pylint: disable=duplicate-except
             self.module.fail_json_aws(e, msg="Could not find target for rule %s" % self.name)
         return self._snakify(targets)['targets']