code: def set_field_type_by_offset(self, field_index, field_type):
      name = self._offset_name_mapping[field_index]
      self._type_mapping[name] = field_type
  
imports: import copy
  from typing import List, Union
  import pandas
  from .utils import AnonymousGenerator
label_desc: Use image node_id 21 for calling the SchemaManager obj's underlying member method code with example usage: obj.set_field_type_by_offset(field_index, field_type) without return types