undefined local variable or method `invoices' for Provider:Class

I'm pretty new to Rails, and I think my app has progressed quicker than my knowledge of Rails/Ruby has ...

I have the following models:

[ -- Begin -- ] class Provider < ActiveRecord::Base   has_many :invoices   has_one :user

  def self.get_invoices     invoices.find(:all)   end end

class User < ActiveRecord::Base   belongs_to :Provider   belongs_to :Consumer

  def invoices_raised     Provider.get_invoices   end

   ...

end [ -- End -- ]

and when I call User.invoices_raised I get this error:

undefined local variable or method `invoices' for Provider:Class

Now I thought that having the "has_many :invoices" line would automatically make the connection and let me access "invoices" like that, but obviously I'm wrong. Anyone care to correct me?

Cheers,

-S