docstr: Find credentials for basic access authentication method. Credentials if
  found stored in Credentials.username and Credentials.password.
  
  Returns
  -------
  bool
      True if valid credentials were found.
      False otherwise.
docstr_tok: ["Find","credentials","for","basic","access","authentication","method",".","Credentials","if","found","stored","in","Credentials.username","and","Credentials.password",".","Returns","--","--","--","-","bool","True","if","valid","credentials","were","found",".","False","otherwise","."]
code: def _get_basic_auth_credentials(self) -> bool:
      """
      Find credentials for basic access authentication method. Credentials if
      found stored in Credentials.username and Credentials.password.
  
      Returns
      -------
      bool
          True if valid credentials were found.
          False otherwise.
      """
      self.logger.log(
          logging.DEBUG,
          "Checking request headers for authentication data",
      )
      if "Authorization" not in self.request.headers:
          self.logger.log(
              logging.INFO, "Authorization header not found"
          )
          return False
  
      auth_header = self.request.headers["Authorization"]
      auth_header_list = auth_header.split(" ")
      if len(auth_header_list) != 2 or auth_header_list[0] != "Basic":
          self.logger.log(
              logging.ERROR,
              f'Unknown authentication method "{auth_header}"',
          )
          return False
  
      try:
          cred = base64.b64decode(auth_header_list[1]).decode("utf-8")
      except (binascii.Error, UnicodeDecodeError) as ex:
          self.logger.log(
              logging.CRITICAL, f"Cannot decode credentials: {str(ex)}"
          )
          return False
  
      login_pwd = cred.split(":")
      if len(login_pwd) != 2:
          self.logger.log(
              logging.ERROR, "Invalid string in encoded credentials"
          )
          return False
  
      self.username = login_pwd[0]
      self.logger.set_tabpy_username(self.username)
      self.password = login_pwd[1]
      return True
  
imports: import base64
  import binascii
  import concurrent
  import json
  import logging
  import tornado.web
  from tabpy.tabpy_server.app.app_parameters import SettingsParameters
  from tabpy.tabpy_server.handlers.util import hash_password
  from tabpy.tabpy_server.handlers.util import AuthErrorStates
  import uuid
label_desc: Use image node_id 6 for calling the BaseHandler obj's underlying member method code with example usage: obj._get_basic_auth_credentials() and returns: True, False, False, False, False