code: def _tail_timedelta(prevs, current, before):
      """Return the concatenated rows of each dataframe in ``prevs`` whose
      index is after the first observation in ``current`` - ``before``.
  
      Parameters
      ----------
      current : DataFrame
      prevs : list of DataFrame objects
      before : timedelta
  
      Returns
      -------
      overlapped : DataFrame
      """
      selected = methods.concat(
          [
              prev[prev.index > (current.index.min() - before)]
              for prev in prevs
          ]
      )
      return selected
  
imports: from __future__ import annotations
  import datetime
  import warnings
  from numbers import Integral
  import pandas
  from pandas.api.types import is_datetime64_any_dtype
  from pandas.core.window import Rolling
  from dask.array.core import normalize_arg
  from dask.base import tokenize
  from dask.blockwise import BlockwiseDepDict
  from dask.dataframe import methods
  from dask.dataframe._compat import check_axis_keyword_deprecation
  from dask.dataframe.core import Scalar, _Frame, _get_divisions_map_partitions, _get_meta_map_partitions, _maybe_from_pandas, apply_and_enforce, new_dd_object, partitionwise_graph
  from dask.dataframe.io import from_pandas
  from dask.dataframe.multi import _maybe_align_partitions
  from dask.dataframe.utils import insert_meta_param_description, is_dask_collection, is_dataframe_like, is_series_like
  from dask.delayed import unpack_collections
  from dask.highlevelgraph import HighLevelGraph
  from dask.typing import no_default
  from dask.utils import M, apply, derived_from, funcname, has_keyword
label_desc: Use image node_id 7 for calling a global function with example usage: _tail_timedelta(prevs, current, before) and returns: selected