class_docstr: A StreamAlert Athena Client for creating tables, databases, and executing queries
  
  Attributes:
      database: Athena database name where tables will be queried
class_docstr_tok: ["A","StreamAlert","Athena","Client","for","creating","tables",",","databases",",","and","executing","queries","Attributes",":","database",":","Athena","database","name","where","tables","will","be","queried"]
docstr: Verify the Athena database being used exists. This is a blocking operation
docstr_tok: ["Verify","the","Athena","database","being","used","exists",".","This","is","a","blocking","operation"]
code: def check_database_exists(self):
      """Verify the Athena database being used exists. This is a blocking operation"""
      response = self.run_query_for_results(
          "SHOW DATABASES LIKE '{}';".format(self.database)
      )
  
      return bool(response and response["ResultSet"]["Rows"])
  
imports: from datetime import datetime
  import posixpath
  import backoff
  import boto3
  from botocore.exceptions import ClientError
  from streamalert.shared.backoff_handlers import backoff_handler, success_handler
  import streamalert.shared.helpers.boto
  from streamalert.shared.logger import get_logger
label_desc: Use image node_id 14 for calling the AthenaClient obj's underlying member method code with example usage: obj.check_database_exists() and returns: bool