Lambda function positional argument error

Question

Hi I am trying to calculate a ratio using lambda function.

This is the code.

ratio = lambda w,x,y,z: ((z*1000*y/3600)/1.05506)/((w*35.32)*x)

df32[('Enthalpy vs DB Ratio','btu')]= df32[[('HRSG DB Flow','T/Hr'),
('Gas calorific value','BTU/Scf'),('HRSG HP STEAM Enthalpy','Kj/Kg'),
('HRSG HP STEAM FLOW','T/h')]].apply(ratio)

I am getting

TypeError: () missing 3 required positional arguments: 'x', 'y', and 'z'

can someone please help? Is this formula problem or it is related to the database problem I am working on?

Thanks for your time.