code: def update_desc_lcin_path(desc,pdesc_level):
      '''
          leftCousin
          previousCousin
          leftCin
          prevCin
          lcin
          pcin
          
          parents are neighbors,and on the left
      '''
      parent_breadth = desc['parent_breadth_path'][-1]
      if(desc['sib_seq']==0):
          if(parent_breadth==0):
              pass
          else:
              parent_lsib_breadth = parent_breadth - 1
              plsib_desc = pdesc_level[parent_lsib_breadth]
              if(plsib_desc['leaf']):
                  pass
              else:
                  lcin_path = copy.deepcopy(plsib_desc['path'])
                  lcin_path.append(plsib_desc['sons_count'] - 1)
                  desc['lcin_path'] = lcin_path
      else:
          pass
      return(descf update_desc_lcin_path(desc,pdesc_level):
      '''
          leftCousin
          previousCousin
          leftCin
          prevCin
          lcin
          pcin
          
          parents are neighbors,and on the left
      '''
      parent_breadth = desc['parent_breadth_path'][-1]
      if(desc['sib_seq']==0):
          if(parent_breadth==0):
              pass
          else:
              parent_lsib_breadth = parent_breadth - 1
              plsib_desc = pdesc_level[parent_lsib_breadth]
              if(plsib_desc['leaf']):
                  pass
              else:
                  lcin_path = copy.deepcopy(plsib_desc['path'])
                  lcin_path.append(plsib_desc['sons_count'] - 1)
                  desc['lcin_path'] = lcin_path
      else:
          pass
      return(desc)
docs: leftCousin
          previousCousin
          leftCin
          prevCin
          lcin
          pcin
          
          parents are neighbors,and on the left