docs: def read_config(self, config_file):
          """
          Parses the specified configuration file and stores the values. Raises
          an InvalidConfigurationFile exception if the file is not well-formed.
          """
          cfg = ConfigParser.SafeConfigParser()
          try:
              cfg.read(config_file)
          except ConfigParser.MissingSectionHeaderError as e:
              # The file exists, but doesn't have the correct format.
              raise exc.InvalidConfigurationFile(e)
  
          def safe_get(section, option, default=None):
              try:
                  return cfg.get(section, option)
              except (ConfigParser.NoSectionError, ConfigParser.NoOptionError):
                  return default
  
          # A common mistake is including credentials in the config file. If any
          # values are found, issue a warning so that the developer can correct
          # this problem.
          creds_found = False
          for section in cfg.sections():
              if section == "settings":
                  section_name = "default"
                  self._default_set = True
              else:
                  section_name = section
              # Check for included credentials
              for key in ("username", "password", "api_key"):
                  if creds_found:
                      break
                  if safe_get(section, key):
                      creds_found = True
              dct = self._settings[section_name] = {}
              dct["region"] = safe_get(section, "region", default_region)
              ityp = safe_get(section, "identity_type")
              if ityp:
                  dct["identity_type"] = _id_type(ityp)
                  dct["identity_class"] = _import_identity(ityp)
              # Handle both the old and new names for this setting.
              debug = safe_get(section, "debug")
              if debug is None:
                  debug = safe_get(section, "http_debug", "False")
              dct["http_debug"] = debug == "True"
              verify_ssl = safe_get(section, "verify_ssl", "True")
              dct["verify_ssl"] = verify_ssl == "True"
              dct["keyring_username"] = safe_get(section, "keyring_username")
              dct["encoding"] = safe_get(section, "encoding", default_encoding)
              dct["auth_endpoint"] = safe_get(section, "auth_endpoint")
              dct["tenant_name"] = safe_get(section, "tenant_name")
              dct["tenant_id"] = safe_get(section, "tenant_id")
              use_servicenet = safe_get(section, "use_servicenet", "False")
              dct["use_servicenet"] = use_servicenet == "True"
              app_agent = safe_get(section, "custom_user_agent")
              if app_agent:
                  # Customize the user-agent string with the app name.
                  dct["user_agent"] = "%s %s" % (app_agent, USER_AGENT)
              else:
                  dct["user_agent"] = USER_AGENT
  
              # If this is the first section, make it the default
              if not self._default_set:
                  self._settings["default"] = self._settings[section]
                  self._default_set = True
          if creds_found:
              warnings.warn("Login credentials were detected in your .pyrax.cfg "
                      "file. These have been ignored, but you should remove "
                      "them and either place them in a credential file, or "
                      "consider using another means of authentication. More "
                      "information on the use of credential files can be found "
                      "in the 'docs/getting_started.md' document.")