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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_project_members(machine, project_id):
 """ Returns list of usernames given a project id """

    try:
        project = Project.objects.get(pid=project_id)
    except Project.DoesNotExist:
        return 'Project not found'

    return [x.username for x in project.group.members.all()]