undefined method

hi,

I am trying to make use of a method located in my model (see below) directly
at my view but I am getting undefined method. how can solve this ?

app/model/operation.rb

def all_products_have_same_posters_count?
    products.all? { |p| p.posters.count == products.first.posters.count }
end

_show.html.haml
    -if @operations.all_products_have_same_posters_count?
      ="foobar"

any recommendations ?

Is @operations possibly an array of operations rather than an operation?
If you think it is just one post the line of code that sets it up.

Otherwise please post the complete error message here.

Colin