Jazz history problem

Hi

i always has this problem wenn i run this line:

history = model.fit([X, a0, c0], list(Y), epochs=100, verbose = 0)

i am not pretty much sure where is the issue?

TypeError: int() argument must be a string, a bytes-like object or a number, not ‘NoneType’

ok i have fixed it up, i forgot that i have changed the X before i run the line