class_docstr: Rule engine to processes rules
class_docstr_tok: ["Rule","engine","to","processes","rules"]
docstr: Verify output is valid
  
  Args:
      output (str): The output to check if its valid
  Returns:
      True (bool): Output is valid
      False (bool): Output is invalid
docstr_tok: ["Verify","output","is","valid","Args",":","output","(","str",")",":","The","output","to","check","if","its","valid","Returns",":","True","(","bool",")",":","Output","is","valid","False","(","bool",")",":","Output","is","invalid"]
code: def _check_valid_output(output):
      """Verify output is valid
  
      Args:
          output (str): The output to check if its valid
      Returns:
          True (bool): Output is valid
          False (bool): Output is invalid
      """
      valid = False
  
      if not isinstance(output, str):
          # Case 1: output is not a string
          #   return False
          LOGGER.warning("Output (%s) is not a string", output)
          valid = False
      elif isinstance(output, str) and ":" not in output:
          # Case 2: output is a string but missing ":"
          #   Log warning and return False
          LOGGER.warning("Output (%s) is missing ':'", output)
  
          valid = False
      else:
          # Case 3: output is a string and contains ":"
          # return True
          valid = True
  
      return valid
  
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 11 for calling the RulesEngine obj's underlying member method code with example usage: obj._check_valid_output(output) and returns: valid