def get(self, id, pk='id', deleted=False):
        try:
            if pk == 'id':
                id = int(id)
            if deleted:
                spec = {pk: id}
            else:
                spec = {pk: id, 'data': {'$exists': 1}}
            fields = {'_id': 0}
            row = self.db.docs.find_one(spec, fields)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return Document(**row)
        raise NotFoundError('%s %s not found' % (pk, id))
def phasor(bch, ax=0):
    """create phasor plot from bch"""
    f1 = bch.machine['p']*bch.dqPar['speed']
    w1 = 2*np.pi*f1
    xd = w1*bch.dqPar['ld'][-1]
    xq = w1*bch.dqPar['lq'][-1]
    r1 = bch.machine['r1']
    i1beta_phasor(bch.dqPar['up'][-1],
                  bch.dqPar['i1'][-1], bch.dqPar['beta'][-1],
                  r1, xd, xq, ax)