You need to provide the parameters as a dictionary:
Imagine you have the onsite potential and the hopping functions as follow:
def onsite(site, V, t):
def hop(site1, site2, B, S):
site1, site2 are the usual variables these functions take. V, t, B and S are parameters needed to execute the functions. You need to provide them for the kwant functions as follows:
Ex: kwant.wave_function(sys, energy=-1, params=dict(B=3,S=5,V=2,t=1) )
So do not use args anymore.
I hope this helps