def sender_name=(v)
      @sender_name = nil
      if (v = sanitize(v)) && v.length > 0
        @sender_name = v
      else
        raise USPSValidationError, "'#{v}' is not a valid string in #{__method__}"
      end
    end
def sender_name=(v)
      @sender_name = nil
      if (v = sanitize(v)) && v.length > 0
        @sender_name = v
      else
        raise USPSValidationError, "'#{v}' is not a valid string in #{__method__}"
      end
    end
The From name in an email sent by the system containing the returns
 label attachment.  Defaults to “Merchant Returns” if a recipient name
 is entered and a sender name is not.
 <em>Optional</em>.