I am new to greta. When I attempted to run the following example and got an error message. Do you know how to fix this issue? Thanks.

library(greta)

x <- as_data(iris$Petal.Length)

y <- as_data(iris$Sepal.Length)

int <- normal(0, 1)

coef <- normal(0, 3)

sd <- student(3, 0, 1, truncation = c(0, Inf))

mean <- int + coef * x

distribution(y) <- normal(mean, sd)

m <- model(int, coef, sd)

Error in py_call_impl(callable, dots$args, dots$keywords) :

ValueError: Tried to convert ‘shape’ to a tensor and failed. Error: Cannot convert a partially known TensorShape to a Tensor: (?, 1, 1)