Hi

I simply want to see the likelihood of an observed binomial variable of some length, where the binomial probability p_i for the different elements in the muli-binomial is given by some function.

(I want to infer lambda 1, given a certain “counts_total” vector.)

```
import numpy as np
import pymc3 as pm
counts_total=np.array([110, 75, 77, 63, 62])
print('shape counts_total: {}'.format(counts_total.shape))
with pm.Model() as model:
lambda1 = pm.Normal('lambda1',10,10)
# fitted_=np.arange(0,5)
p=np.exp(-lambda1*(fitted_+0.5))*(np.exp(0.5*lambda1)-np.exp(-0.5*lambda1))
p=np.ones(5)*0.1
b = pm.Binomial('b',n=1000,p=p,shape=len(fitted_),observed=counts_total[:5])
print(b.logp())
```

This gives me the error:

**Missing required input: lambda1**

Looks as if lambda1 was not initialized?