How to use the thermo.stream.Stream function in thermo

assert_allclose(m.Qls, flow_inputs['Qls'])
        assert_allclose(m.Qgs, flow_inputs['Qgs'])


    with pytest.raises(Exception):
        # two compositions specified
        Stream(['water', 'ethanol'], ns=[6, 4], ws=[.4, .6], T=300, P=1E5)
    with pytest.raises(Exception):
        # two flow rates specified
        Stream(['water', 'ethanol'], ns=[6, 4], n=10, T=300, P=1E5)
    with pytest.raises(Exception):
        # no composition
        Stream(['water', 'ethanol'], n=1, T=300, P=1E5)
    with pytest.raises(Exception):
        # no flow rate
        Stream(['water', 'ethanol'], zs=[.5, .5], T=300, P=1E5)

assert_allclose(m.n, inputs['n'])
            assert_allclose(m.m, inputs['m'])
            assert_allclose(m.Q, inputs['Q'])
            assert_allclose(m.ns, flow_inputs['ns'])
            assert_allclose(m.ms, flow_inputs['ms'])
            assert_allclose(m.Qls, flow_inputs['Qls'])
            assert_allclose(m.Qgs, flow_inputs['Qgs'])

    # Test ordereddict input with flow rates being given as dicts
    for key, val in flow_inputs.items():
        d = OrderedDict()
        for i, j in zip(IDs, val):
            d.update({i: j})
        
        m = Stream(T=300, P=1E5, **{key:d})
        assert_allclose(m.n, inputs['n'])
        assert_allclose(m.m, inputs['m'])
        assert_allclose(m.Q, inputs['Q'])
        assert_allclose(m.ns, flow_inputs['ns'])
        assert_allclose(m.ms, flow_inputs['ms'])
        assert_allclose(m.Qls, flow_inputs['Qls'])
        assert_allclose(m.Qgs, flow_inputs['Qgs'])


    with pytest.raises(Exception):
        # two compositions specified
        Stream(['water', 'ethanol'], ns=[6, 4], ws=[.4, .6], T=300, P=1E5)
    with pytest.raises(Exception):
        # two flow rates specified
        Stream(['water', 'ethanol'], ns=[6, 4], n=10, T=300, P=1E5)
    with pytest.raises(Exception):

m = Stream(T=300, P=1E5, **{key:d})
        assert_allclose(m.n, inputs['n'])
        assert_allclose(m.m, inputs['m'])
        assert_allclose(m.Q, inputs['Q'])
        assert_allclose(m.ns, flow_inputs['ns'])
        assert_allclose(m.ms, flow_inputs['ms'])
        assert_allclose(m.Qls, flow_inputs['Qls'])
        assert_allclose(m.Qgs, flow_inputs['Qgs'])


    with pytest.raises(Exception):
        # two compositions specified
        Stream(['water', 'ethanol'], ns=[6, 4], ws=[.4, .6], T=300, P=1E5)
    with pytest.raises(Exception):
        # two flow rates specified
        Stream(['water', 'ethanol'], ns=[6, 4], n=10, T=300, P=1E5)
    with pytest.raises(Exception):
        # no composition
        Stream(['water', 'ethanol'], n=1, T=300, P=1E5)
    with pytest.raises(Exception):
        # no flow rate
        Stream(['water', 'ethanol'], zs=[.5, .5], T=300, P=1E5)

def test_Stream():   
    Stream(['H2', 'NH3', 'CO', 'Ar', 'CH4', 'N2'],
           zs=[.7371, 0, .024, .027, .013, .2475], 
    T=500, P=20.5E5, m=300)

def test_sub_streams():
    with pytest.raises(Exception):
        # remove a component not present
        Stream(['water', 'ethanol'], ns=[1, 2], T=300, P=1E5) - Stream(['decane'], ns=[.5], T=300, P=1E5)

    with pytest.raises(Exception):
        # Remove too much of a component 
        Stream(['water', 'ethanol'], ns=[1, 2], T=300, P=1E5) - Stream(['ethanol'], ns=[3], T=300, P=1E5)

    # Take a component completely away
    no_ethanol = Stream(['water', 'ethanol'], ns=[1, 2], T=300, P=1E5) - Stream(['ethanol'], ns=[2], T=300, P=1E5)
    assert len(no_ethanol.zs) == 1
    assert_allclose(no_ethanol.zs, 1)
    assert_allclose(no_ethanol.n, 1)
    assert_allclose(no_ethanol.m, 0.01801528)
    
    # basic case
    m = Stream(['water', 'ethanol'], ns=[1, 2], T=300, P=1E5) - Stream(['ethanol'], ns=[1], T=300, P=1E5)
    assert_allclose(m.ns, [1, 1])
    
    # test case
    m = Stream(['water', 'ethanol', 'decane', 'pentane'], ns=[1, 2, 3, 1E-9], T=300, P=1E5) - Stream(['ethanol'], ns=[2], T=300, P=1E5)
    assert_allclose(m.ns, [1, 3.0, 1e-09])
    assert m.CASs == ['7732-18-5', '124-18-5', '109-66-0']

assert_allclose(m.Q, inputs['Q'])
        assert_allclose(m.ns, flow_inputs['ns'])
        assert_allclose(m.ms, flow_inputs['ms'])
        assert_allclose(m.Qls, flow_inputs['Qls'])
        assert_allclose(m.Qgs, flow_inputs['Qgs'])


    with pytest.raises(Exception):
        # two compositions specified
        Stream(['water', 'ethanol'], ns=[6, 4], ws=[.4, .6], T=300, P=1E5)
    with pytest.raises(Exception):
        # two flow rates specified
        Stream(['water', 'ethanol'], ns=[6, 4], n=10, T=300, P=1E5)
    with pytest.raises(Exception):
        # no composition
        Stream(['water', 'ethanol'], n=1, T=300, P=1E5)
    with pytest.raises(Exception):
        # no flow rate
        Stream(['water', 'ethanol'], zs=[.5, .5], T=300, P=1E5)

def test_add_streams():
    # simple example, same components
    ans = {'zs': [0.4, 0.6], 'ws': [0.20679185022051716, 0.7932081497794828], 'm': 0.34847176, 'n': 10}
    prod = Stream(['water', 'ethanol'], ns=[1, 2], T=300, P=1E5) + Stream(['water', 'ethanol'], ns=[3, 4], T=300, P=1E5)
    assert_allclose(prod.zs, ans['zs'])
    assert_allclose(prod.ws, ans['ws'])
    assert_allclose(prod.m, ans['m'])
    assert_allclose(prod.n, ans['n'])

    # add a not a stream
    with pytest.raises(Exception):
        Stream(['decane', 'octane'],  T=300, P=1E5, ns=[4, 5]) +1
    
    # Add two streams, check they're the same if added in a different order
    ans = {'zs': [1/6., 1/3., 1/3., 1/6.], 
           'ws': [0.12364762781718204, 0.3687607770917325, 0.3080280163630483, 0.1995635787280373],
           'm': 0.92382298, 'n': 6}
    
    S1 = Stream(['decane', 'octane'],  T=300, P=1E5, ns=[2, 1])
    S2 = Stream(['Dodecane', 'Tridecane'],  T=300, P=1E5, ns=[2, 1])

flow_inputs = {'ns': [2027.0435669809347, 1377.998529332439], 'ms': [36.517757431360295, 63.482242568639705],
                  'Qls': [0.036643922302061455, 0.08101987400787004], 'Qgs': [48.673177307086064, 32.448784871390714]}
    
    for key1, val1 in compositions.items():
        for key2, val2 in inputs.items():
            m = Stream(['water', 'ethanol'], T=300, P=1E5, **{key1:val1, key2:val2})
            assert_allclose(m.n, inputs['n'])
            assert_allclose(m.m, inputs['m'])
            assert_allclose(m.Q, inputs['Q'])
            assert_allclose(m.ns, flow_inputs['ns'])
            assert_allclose(m.ms, flow_inputs['ms'])
            assert_allclose(m.Qls, flow_inputs['Qls'])
            assert_allclose(m.Qgs, flow_inputs['Qgs'])
            
    for key, val in flow_inputs.items():
        m = Stream(['water', 'ethanol'], T=300, P=1E5, **{key:val})
        assert_allclose(m.n, inputs['n'])
        assert_allclose(m.m, inputs['m'])
        assert_allclose(m.Q, inputs['Q'])
        assert_allclose(m.ns, flow_inputs['ns'])
        assert_allclose(m.ms, flow_inputs['ms'])
        assert_allclose(m.Qls, flow_inputs['Qls'])
        assert_allclose(m.Qgs, flow_inputs['Qgs'])

    # Test ordereddict input
    IDs = ['water', 'ethanol']
    
    for key1, val1 in compositions.items():
        d = OrderedDict()
        for i, j in zip(IDs, val1):
            d.update({i: j})

ns_self[i] = 0.
                elif relative_difference_product < 1E-12:
                    ns_self[i] = 0.
                else:
                    ns_self[i] = ns_self[i] - nj


        # Remove now-empty streams:
        ns_product = []
        CASs_product = []
        for n, CAS in zip(ns_self, self.CASs):
            if n != 0:
                ns_product.append(n)
                CASs_product.append(CAS)
        # Create the resulting stream
        return Stream(IDs=CASs_product, ns=ns_product, T=self.T, P=self.P)

def __add__(self, other):
        if not isinstance(other, Stream):
            raise Exception('Adding to a stream requires that the other object '
                            'also be a stream.')
        
        if (set(self.CASs) == set(other.CASs)) and (len(self.CASs) == len(other.CASs)):
            cmps = self.CASs
        else:
            cmps = sorted(list(set((self.CASs + other.CASs))))
        mole = self.n + other.n
        moles = []
        for cmp in cmps:
            moles.append(0)
            if cmp in self.CASs:
                ind = self.CASs.index(cmp)
                moles[-1] += self.zs[ind]*self.n
            if cmp in other.CASs:
                ind = other.CASs.index(cmp)