Is this the best pattern for deprecating a method paramater?

deprecated.rb

module FullContact
  class Client
    module Person
      # Returns extended information for a given person (email, phone, twitter or facebook)
      #
       def person(options={})
         if options.is_a?(String)
           warn "[DEPRECATION] supplying an email address directly is deprecated.  Please use {email: #{options}} instead."
           options = {:email => options}
         end
        response = get('person', options)
        format.to_s.downcase == 'xml' ? response['person'] : response
      end
     end
  end
end

I should have pointed out the method initially looked like this:

def person(email)
response = get('person', email: email)
#....
end