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We thought it was confusing for this to return `true` if the address is
not in a nexus region. But that's what it does for all international
addresses. Hopefully this comment is instructive to anyone who needs to
understand this check in the future.

Co-Authored-By: Chris Todorov <chris@super.gd>

lib/super_good/solidus_taxjar/calculator_helper.rb

@@ -51,6 +51,8 @@ def state_required?(country)
 
       private
 
+      # Nexus regions are only a concept for US states. For non-US addresses
+      # we always want to defer to the configuration in TaxJar.
       def address_in_nexus_region?(address)
         return true unless address&.country&.iso == "US"