class_docstr: Download data from https://rajpurkar.github.io/SQuAD-explorer/
  Will return tuples of (doc, question, answer, answer_start, has_answer)
class_docstr_tok: ["Download","data","from","https",":","\/\/rajpurkar.github.io\/SQuAD-explorer\/","Will","return","tuples","of","(","doc",",","question",",","answer",",","answer_start",",","has_answer",")"]
code: def from_config(cls, config: Config, schema=DEFAULT_SCHEMA):
      return cls(
          train_filename=config.train_filename,
          test_filename=config.test_filename,
          eval_filename=config.eval_filename,
          ignore_impossible=config.ignore_impossible,
          max_character_length=config.max_character_length,
          min_overlap=config.min_overlap,
          delimiter=config.delimiter,
          quoted=config.quoted,
      )
  
imports: import json
  import math
  from random import choice
  from typing import List, Optional
  from pytext.data.sources.data_source import DataSource, generator_property, JSONString, SafeFileWrapper
  from pytext.data.sources.tsv import TSV
  from pytext.utils.file_io import PathManager
  from pytext.utils.path import get_absolute_path
label_desc: Use image node_id 1 for calling the SquadDataSource obj's underlying member method code with example usage: obj.from_config(cls, config, schema) and returns: cls