code: def _format_coord(freq, t, y) -> str:
      time_period = Period(ordinal=int(t), freq=freq)
      return f"t = {time_period}  y = {y:8f}"
  
imports: from __future__ import annotations
  from datetime import timedelta
  import functools
  from typing import TYPE_CHECKING, cast
  import numpy
  from pandas._libs.tslibs import BaseOffset, Period, to_offset
  from pandas._libs.tslibs.dtypes import FreqGroup
  from pandas.core.dtypes.generic import ABCDatetimeIndex, ABCPeriodIndex, ABCTimedeltaIndex
  from pandas.io.formats.printing import pprint_thing
  from pandas.plotting._matplotlib.converter import TimeSeries_DateFormatter, TimeSeries_DateLocator, TimeSeries_TimedeltaFormatter
  from pandas.tseries.frequencies import get_period_alias, is_subperiod, is_superperiod
label_desc: Use image node_id 13 for calling a global function with example usage: _format_coord(freq, t, y) and returns: str, time_period, str, y