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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 list_projects(root, backend=os.listdir):
 """List projects at `root` Arguments: root (str):
 Absolute path to the `be` root directory, typically the current working directory. """

    projects = list()
    for project in sorted(backend(root)):
        abspath = os.path.join(root, project)
        if not isproject(abspath):
            continue
        projects.append(project)
    return projects