class_docstr: Rule engine to processes rules
class_docstr_tok: ["Rule","engine","to","processes","rules"]
docstr: Return lookup table by table name
  
  The rules engine supports to load arbitrary json files from S3 buckets into
  memory for quick reference while writing rules. This information is stored
  in class variable `_LOOKUP_TABLES` which is a dictionary. Json file name
  without extension will the key name(a.k.a table_name), and json content
  will be the value.
  
  Args:
      table_name (str): Lookup table name. It is also the json file name without
          extension.
  
  Returns:
      LookupTable: An instance of a LookupTable
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code: def get_lookup_table(cls, table_name):
      """Return lookup table by table name
  
      The rules engine supports to load arbitrary json files from S3 buckets into
      memory for quick reference while writing rules. This information is stored
      in class variable `_LOOKUP_TABLES` which is a dictionary. Json file name
      without extension will the key name(a.k.a table_name), and json content
      will be the value.
  
      Args:
          table_name (str): Lookup table name. It is also the json file name without
              extension.
  
      Returns:
          LookupTable: An instance of a LookupTable
      """
      return cls._lookup_tables.table(table_name)
  
imports: from datetime import datetime, timedelta
  from os import environ
  from streamalert.shared.publisher import AlertPublisherRepository
  from streamalert.rules_engine.alert_forwarder import AlertForwarder
  from streamalert.rules_engine.threat_intel import ThreatIntel
  from streamalert.shared import resources, RULES_ENGINE_FUNCTION_NAME
  from streamalert.shared.alert import Alert
  from streamalert.shared.config import load_config
  from streamalert.shared.importer import import_folders
  from streamalert.shared.logger import get_logger
  from streamalert.shared.lookup_tables.core import LookupTables
  from streamalert.shared.metrics import MetricLogger
  from streamalert.shared.rule import Rule
  from streamalert.shared.rule_table import RuleTable
  from streamalert.shared.stats import RuleStatisticTracker
label_desc: Use image node_id 3 for calling the RulesEngine obj's underlying member method code with example usage: obj.get_lookup_table(cls, table_name) and returns: cls