docs: def trim_tree(self, node):
          """trims the tree for any empty data nodes"""
          data_len = len(node[-1])
  
          if node[1] == -1 and node[2] == -1:
              if data_len == 0:
                  return 1
              else:
                  return 0
          else:
              if self.trim_tree(node[1]) == 1:
                  node[1] = -1
  
              if self.trim_tree(node[2]) == 1:
                  node[2] = -1
  
              if node[1] == -1 and node[2] == -1:
                  if data_len == 0:
                      return 1
                  else:
                      return 0