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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_role(role_id,**kwargs):
 """ Get a role by its ID. """

    try:
        role = db.DBSession.query(Role).filter(Role.id==role_id).one()
        return role
    except NoResultFound:
        raise HydraError("Role not found (role_id={})".format(role_id))