diff --git a/atlassian/bitbucket/cloud/repositories/__init__.py b/atlassian/bitbucket/cloud/repositories/__init__.py
index c0ab116c7..e1573d6ea 100644
--- a/atlassian/bitbucket/cloud/repositories/__init__.py
+++ b/atlassian/bitbucket/cloud/repositories/__init__.py
@@ -263,7 +263,7 @@ def __init__(self, data, *args, **kwargs):
         self.__hooks = Hooks(
             "{}/hooks".format(self.url),
             data={"links": {"hooks": {"href": "{}/hooks".format(self.url)}}},
-            **self._new_session_args,
+            **self._new_session_args
         )
         self.__default_reviewers = DefaultReviewers("{}/default-reviewers".format(self.url), **self._new_session_args)
         self.__deployment_environments = DeploymentEnvironments(
diff --git a/atlassian/confluence.py b/atlassian/confluence.py
index f8d102f4b..274c9b46b 100644
--- a/atlassian/confluence.py
+++ b/atlassian/confluence.py
@@ -1340,7 +1340,7 @@ def download_attachments_from_page(self, page_id, path=None):
                 if not file_name:
                     file_name = attachment["id"]  # if the attachment has no title, use attachment_id as a filename
                 download_link = self.url + attachment["_links"]["download"]
-                r = self._session.get(f"{download_link}")
+                r = self._session.get(str(download_link))
                 file_path = os.path.join(path, file_name)
                 with open(file_path, "wb") as f:
                     f.write(r.content)
diff --git a/atlassian/jira.py b/atlassian/jira.py
index bd24798a6..c5a1f5eeb 100644
--- a/atlassian/jira.py
+++ b/atlassian/jira.py
@@ -255,11 +255,11 @@ def download_attachments_from_issue(self, issue, path=None, cloud=True):
                 path = os.getcwd()
             issue_id = self.issue(issue, fields="id")["id"]
             if cloud:
-                url = self.url + f"/secure/issueAttachments/{issue_id}.zip"
+                url = self.url + "/secure/issueAttachments/{}.zip".format(issue_id)
             else:
-                url = self.url + f"/secure/attachmentzip/{issue_id}.zip"
+                url = self.url + "/secure/attachmentzip/{}.zip".format(issue_id)
             response = self._session.get(url)
-            attachment_name = f"{issue_id}_attachments.zip"
+            attachment_name = "{}_attachments.zip".format(issue_id)
             file_path = os.path.join(path, attachment_name)
             # if Jira issue doesn't have any attachments _session.get request response will return 22 bytes of PKzip format
             file_size = sum(len(chunk) for chunk in response.iter_content(8196))
diff --git a/tox.ini b/tox.ini
index b8c071931..090589552 100644
--- a/tox.ini
+++ b/tox.ini
@@ -35,7 +35,7 @@ commands = pylint {[base]linting_targets}
 
 [testenv:black]
 basepython = python3
-target-version = ["py37"]
+target-version = ["py27", "py37"]
 skip_install = true
 deps = black
 commands = black --check --diff {[base]linting_targets} --exclude __pycache__