```ruby
require "wisper"
require "dry/transaction/step_failure"

module Dry
  module Transaction
    # @api private
    class Step
      include Wisper::Publisher
      include Dry::Monads::Either::Mixin

      attr_reader :step_adapter
      attr_reader :step_name
      attr_reader :operation_name
      attr_reader :operation
      attr_reader :options
      attr_reader :call_args

      def initialize(step_adapter, step_name, operation_name, operation, options, call_args = [])
        @step_adapter = step_adapter
        @step_name = step_name
        @operation_name = operation_name
        @operation = operation
        @options = options
        @call_args = call_args
      end

      def with_call_args(*call_args)
        self.class.new(step_adapter, step_name, operation_name, operation, options, call_args)
      end

      def call(input)
        args = call_args + [input]
        result = step_adapter.call(self, *args)

        result.fmap { |value|
          broadcast :"#{step_name}_success", value
          value
        }.or { |value|
          broadcast :"#{step_name}_failure", *args, value
          Left(StepFailure.new(step_name, value))
        }
      end

      def arity
        operation.is_a?(Proc) ? operation.arity : operation.method(:call).arity
      end
    end
  end
end
```

Add missing require for dry-monads either
user
```ruby
require "dry/monads/either"
require "wisper"
require "dry/transaction/step_failure"

module Dry
  module Transaction
    # @api private
    class Step
      include Wisper::Publisher
      include Dry::Monads::Either::Mixin

      attr_reader :step_adapter
      attr_reader :step_name
      attr_reader :operation_name
      attr_reader :operation
      attr_reader :options
      attr_reader :call_args

      def initialize(step_adapter, step_name, operation_name, operation, options, call_args = [])
        @step_adapter = step_adapter
        @step_name = step_name
        @operation_name = operation_name
        @operation = operation
        @options = options
        @call_args = call_args
      end

      def with_call_args(*call_args)
        self.class.new(step_adapter, step_name, operation_name, operation, options, call_args)
      end

      def call(input)
        args = call_args + [input]
        result = step_adapter.call(self, *args)

        result.fmap { |value|
          broadcast :"#{step_name}_success", value
          value
        }.or { |value|
          broadcast :"#{step_name}_failure", *args, value
          Left(StepFailure.new(step_name, value))
        }
      end

      def arity
        operation.is_a?(Proc) ? operation.arity : operation.method(:call).arity
      end
    end
  end
end
```
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