new_contents: #!/usr/bin/env python
  # -*- encoding: utf-8 -*-
  #
  # Copyright (c) 2015 ASMlover. All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions
  # are met:
  #
  #  * Redistributions of source code must retain the above copyright
  #    notice, this list ofconditions and the following disclaimer.
  #
  #  * Redistributions in binary form must reproduce the above copyright
  #    notice, this list of conditions and the following disclaimer in
  #    the documentation and/or other materialsprovided with the
  #    distribution.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  # POSSIBILITY OF SUCH DAMAGE.
  
  from error import UnimplementedFunctionError
  from interface import Eval, Egal
  
  class Sequence(Eval, Egal):
      def __init__(self):
          self.data = None
  
      def car(self):
          return self.data[0]
  
      def cdr(self):
          raise UnimplementedFunctionError(
                  'Function not yet implemented for ', 
                  self.__class__.__name__)
      def cons(self, e):
          raise UnimplementedFunctionError(
                  'Function not yet implemented for ', 
                  self.__class__.__name__)
  
      def __iter__(self):
          return self.data.__iter__()
  
      def __len__(self):
          return len(self.data)
  
      def __contains__(self, e):
          return e in self.data
  
      def __getitem__(self, e):
          return self.data[e]
  
      def __eq__(self, rhs):
          if not isinstance(rhs, Sequence):
              return False
  
          if len(self) != len(rhs):
              return False
  
          for i in range(len(self.data)):
              if self.data[i] != rhs.data[i]:
                  return False
  
          return True
  
  class List(Sequence):
      def __init__(self, l=None):
          super(List, self).__init__()
  
          self.data = [] if l is None else l
  
      def cdr(self):
          try:
              return List(self.data[1:])
          except:
              return List([])
  
      def cons(self, e):
          result = List(self.data[:])
          result.data.insert(0, e)
          return result
  
      def eval(self, env, args=None):
          form = self.car().eval(env)
          return form.eval(env, self.cdr())
  
      def __repr__(self):
          if self.data == []:
              return '()'
  
          result = '(%s' % self.data[0]
          for e in selfd.data[1:]:
              result = '%s %s' % (result, e)
          return result + ')'
  
subject: add sequence for eLisp