code: def get_field_name(self, offset):
      if offset >= len(self._offset_name_mapping):
          raise ValueError(f"Offset={offset} is out out bound")
  
      return self._offset_name_mapping[offset]
  
imports: import copy
  from typing import List, Union
  import pandas
  from .utils import AnonymousGenerator
label_desc: Use image node_id 18 for calling the SchemaManager obj's underlying member method code with example usage: obj.get_field_name(offset) and returns: self