Together with @mbaudin47 , we noticed that common covariance models, such as SquaredExponential, MaternModel, AbsoluteExponential have a constructor that takes the value of the amplitude parameter, which is always a scalar value, but require the user to pass it as a one-dimensional list ( Must be of size equal to 1. By default, equal to  )
Wouldn’t it make more sense for these constructors to take the amplitude as an ot.Scalar?
I guess that this issue comes from the fact that the parent class, CovarianceModel, is also parent to other classes that can have multi-dimensional amplitude parameters (e.g., TensorizedCovarianceModel). Would it make sense to override the amplitude parameter type for the classes that can only have scalar in order to ensure coherence and consistency in the aforementioned covariance models constructors?