Fuzzy Logic in [R]

I want to create linguistic variables for a specialized system with R . However, in the documentation, I only found one way to do with trapezoid function and it is with standard error. How should I correct it? Follow the code.

variables <- set(
  VAZAO = fuzzy_variable(
           ALTA  = fuzzy_trapezoid(corners = c(70,80, 100, 100)),
           MEDIA = fuzzy_trapezoid(corners = c(20, 40, 60, 80)),
           BAIXA = fuzzy_trapezoid(corners = c(0, 0, 20, 40)))
 )