def set_init_conc(self, **kwargs):
    'set the initial concentrations [mg/L] of the CSTR.'
    Cs = np.zeros(len(self.components))
    cmpx = self.components.index
    for (k, v) in kwargs.items():
        Cs[cmpx(k)] = v
    self._concs = Cs
set the initial concentrations [mg/L] of the CSTR.
def set_init_conc(self, **kwargs):
    
    Cs = np.zeros(len(self.components))
    cmpx = self.components.index
    for (k, v) in kwargs.items():
        Cs[cmpx(k)] = v
    self._concs = Cs