It is likely that you used a MergeRequest, GroupMergeRequest, Issue or GroupIssue object. These objects cannot be edited. But you can create a new ProjectMergeRequest or ProjectIssue object to apply changes. For example:

issue = gl.issues.list()[0]
project = gl.projects.get(issue.project_id, lazy=True)
editable_issue = project.issues.get(issue.iid, lazy=True)
# you can now edit the object

See the :ref:`merge requests example <merge_requests_examples>` and the :ref:`issues examples <issues_examples>`.

python-gitlab doesn't provide an API to clone a project. You have to use a git library or call the git command.

The git URI is exposed in the ssh_url_to_repo attribute of Project objects.

Example:

import subprocess

project = gl.projects.create(data)  # or gl.projects.get(project_id)
print(project.attributes)  # displays all the attributes
git_url = project.ssh_url_to_repo
subprocess.call(['git', 'clone', git_url])