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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 roles_for_user(request, user, project=None, domain=None):
 """Returns a list of user roles scoped to a project or domain."""

    manager = keystoneclient(request, admin=True).roles
    if VERSIONS.active < 3:
        return manager.roles_for_user(user, project)
    else:
        return manager.list(user=user, domain=domain, project=project)