[R] Problem with contrast() - nonconforming number of contrast coefficients

Hello, I have written this question on a problem that I have with the method contrast() in this Stackoverflow. Is here anybody who can advise me on a method to do what I aim to do? https://stackoverflow.com/questions/65267565/r-lsmeans-contrast-error-nonconforming-number-of-contrast-coefficients

[R] Problem with contrast

Hello All, I am trying to estimate a generalized linear model using a single dummy variable (bilat). I want to use contr.sum, in which (please correct me if I am wrong) the implicit coefficient on the contrast equals the negative of the sum of all estimated coefficients. I cannot get the contra