class_docstr: Leafs are basically tokens with a better API. Leafs exactly know where they
  were defined and what text preceeds them.
code: def start_pos(self, value):
      self.line = value[0]
      self.column = value[1]
  
imports: import sys
  from abc import abstractmethod, abstractproperty
  from parso._compatibility import utf8_repr, encoding
  from parso.utils import split_lines
label_desc: Use image node_id 3 for calling the Leaf obj's underlying member method code with example usage: obj.start_pos(value) without return types