Seeking Clarification on Key Existence in PyBox Dictionary

[hidonkey2018]

@douglowe
I am a bit confused by this line of code: if value in dict[react].
https://github.com/loftytopping/PyBox/blob/3efd0a69e15dc9ba8f965342ea47d295c7033f40/Parse_eqn_file.py#L282C1-L282C65

This line of code is located within a 'product' looping block. From my understanding of this block of code, I presume that the if statement should check the key existence in gain_dict[product] instead of gain_dict[reactant]. However, I am not sure if my assumption is correct. I have tried using both dict[product] and dict[react], and they returned slightly different results.