Trying to do spline interpolating inside a pymc3 model

I am trying to perform a numpy.interpolate.spline interpolation inside a pymc3 model.

before the model I do the following

tciI = []
for iwvl, amatch in enumerate(matchDict['match']):
    tckSum = amatch['tckSum']

with pm.Model() as model:
t0 = pm.Uniform(‘t0’, lower = 5.5, upper = 6.2, testval = logT[0])
t1 = pm.Uniform(‘t1’, lower = t0+0.01, upper = 6.3, testval = logT[1])
em = pm.Uniform(‘em’, lower=27., upper= 27.4, shape=2)
for iwvl, atck in enumerate(tckI):
logContrib0 = interpolate.splev(t0,atck,der=0)
I get the following error

Cannot cast array data from dtype(‘O’) to dtype(‘float64’) according to the rule ‘safe’

I have created a similar model before that suggests my problems are with theano