code: def resolve_one(self, key: str) -> "DictStrAny":
      return self._each_iter(key)
  
imports: import logging
  import os
  from collections.abc import Mapping, Sequence
  from copy import deepcopy
  from itertools import product
  from typing import TYPE_CHECKING, Any, Dict, List, NamedTuple, Optional, Tuple, Type, Union
  from funcy import collecting, first, isa, join, reraise
  from dvc.exceptions import DvcException
  from dvc.log import logger
  from dvc.parsing.interpolate import ParseError
  from dvc.utils.objects import cached_property
  from .context import Context, ContextError, KeyNotInContext, MergeError, Node, VarsAlreadyLoaded
  from .interpolate import check_recursive_parse_errors, is_interpolated_string, recurse, to_str
label_desc: Use image node_id 11 for calling the MatrixDefinition obj's underlying member method code with example usage: obj.resolve_one(key) and returns: self