code: def cdr(ol,**kwargs):
      '''
          from elist.elist import *
          ol=[1,2,3,4]
          id(ol)
          new = cdr(ol)
          new
          id(new)
          ####
          ol=[1,2,3,4]
          id(ol)
          rslt = cdr(ol,mode="original")
          rslt
          id(rslt)
      '''
      if('mode' in kwargs):
          mode = kwargs['mode']
      else:
          mode = "new"
      if(mode == "new"):
          cpol = copy.deepcopy(ol)
          return(cpol[1:])
      else:
          ol.pop(0)
          return(olf cdr(ol,**kwargs):
      '''
          from elist.elist import *
          ol=[1,2,3,4]
          id(ol)
          new = cdr(ol)
          new
          id(new)
          ####
          ol=[1,2,3,4]
          id(ol)
          rslt = cdr(ol,mode="original")
          rslt
          id(rslt)
      '''
      if('mode' in kwargs):
          mode = kwargs['mode']
      else:
          mode = "new"
      if(mode == "new"):
          cpol = copy.deepcopy(ol)
          return(cpol[1:])
      else:
          ol.pop(0)
          return(ol)
docs: from elist.elist import *
          ol=[1,2,3,4]
          id(ol)
          new = cdr(ol)
          new
          id(new)
          ####
          ol=[1,2,3,4]
          id(ol)
          rslt = cdr(ol,mode="original")
          rslt
          id(rslt)