code: def _parser_dispatch(flavor):
      """Choose the parser based on the input flavor.
  
      Parameters
      ----------
      flavor : str
          The type of parser to use. This must be a valid backend.
  
      Returns
      -------
      cls : _HtmlFrameParser subclass
          The parser class based on the requested input flavor.
  
      Raises
      ------
      ValueError
          * If `flavor` is not a valid backend.
      ImportError
          * If you do not have the requested `flavor`
      """
      valid_parsers = list(_valid_parsers.keys())
      if flavor not in valid_parsers:
          raise ValueError(
              "{invalid!r} is not a valid flavor, valid flavors "
              "are {valid}".format(invalid=flavor, valid=valid_parsers)
          )
  
      if flavor in ("bs4", "html5lib"):
          if not _HAS_HTML5LIB:
              raise ImportError("html5lib not found, please install it")
          if not _HAS_BS4:
              raise ImportError(
                  "BeautifulSoup4 (bs4) not found, please install it"
              )
          import bs4
  
          if LooseVersion(bs4.__version__) <= LooseVersion("4.2.0"):
              raise ValueError(
                  "A minimum version of BeautifulSoup 4.2.1 "
                  "is required"
              )
  
      else:
          if not _HAS_LXML:
              raise ImportError("lxml not found, please install it")
      return _valid_parsers[flavor]
  
imports: from distutils.version import LooseVersion
  import numbers
  import os
  import re
  import pandas.compat
  from pandas.compat import binary_type, iteritems, lmap, lrange, raise_with_traceback, string_types, u
  from pandas.errors import AbstractMethodError, EmptyDataError
  from pandas.core.dtypes.common import is_list_like
  from pandas import Series
  from pandas.io.common import _is_url, _validate_header_arg, urlopen
  from pandas.io.formats.printing import pprint_thing
  from pandas.io.parsers import TextParser
label_desc: Use image node_id 8 for calling a global function with example usage: _parser_dispatch(flavor) and returns: _valid_parsers