code: def _make_reader(
      self, f: IO[str] | ReadCsvBuffer[str]
  ) -> Iterator[list[str]]:
      sep = self.delimiter
  
      if sep is None or len(sep) == 1:
          if self.lineterminator:
              raise ValueError(
                  "Custom line terminators not supported in python parser (yet)"
              )
  
          class MyDialect(csv.Dialect):
              delimiter = self.delimiter
              quotechar = self.quotechar
              escapechar = self.escapechar
              doublequote = self.doublequote
              skipinitialspace = self.skipinitialspace
              quoting = self.quoting
              lineterminator = "\n"
  
          dia = MyDialect
  
          if sep is not None:
              dia.delimiter = sep
          else:
              # attempt to sniff the delimiter from the first valid line,
              # i.e. no comment line and not in skiprows
              line = f.readline()
              lines = self._check_comments([[line]])[0]
              while self.skipfunc(self.pos) or not lines:
                  self.pos += 1
                  line = f.readline()
                  lines = self._check_comments([[line]])[0]
              lines_str = cast(list[str], lines)
  
              # since `line` was a string, lines will be a list containing
              # only a single string
              line = lines_str[0]
  
              self.pos += 1
              self.line_pos += 1
              sniffed = csv.Sniffer().sniff(line)
              dia.delimiter = sniffed.delimiter
  
              # Note: encoding is irrelevant here
              line_rdr = csv.reader(StringIO(line), dialect=dia)
              self.buf.extend(list(line_rdr))
  
          # Note: encoding is irrelevant here
          reader = csv.reader(f, dialect=dia, strict=True)
  
      else:
  
          def _read():
              line = f.readline()
              pat = re.compile(sep)
  
              yield pat.split(line.strip())
  
              for line in f:
                  yield pat.split(line.strip())
  
          reader = _read()
  
      return reader
  
imports: from __future__ import annotations
  from collections import abc, defaultdict
  import csv
  from io import StringIO
  import re
  from typing import IO, TYPE_CHECKING, DefaultDict, Literal, cast
  import warnings
  import numpy
  from pandas._libs import lib
  from pandas.errors import EmptyDataError, ParserError, ParserWarning
  from pandas.util._decorators import cache_readonly
  from pandas.util._exceptions import find_stack_level
  from pandas.core.dtypes.common import is_bool_dtype, is_integer, is_numeric_dtype
  from pandas.core.dtypes.inference import is_dict_like
  from pandas.io.common import dedup_names, is_potential_multi_index
  from pandas.io.parsers.base_parser import ParserBase, parser_defaults
label_desc: Use image node_id 3 for calling the PythonParser obj's underlying member method code with example usage: obj._make_reader(f) and returns: reader