text: """Implementation of Rule L040."""
  
  from typing import Tuple, List
  
  from sqlfluff.core.rules.doc_decorators import (
      document_configuration,
      document_fix_compatible,
  )
  from sqlfluff.rules.L010 import Rule_L010
  
  
  @document_configuration
  @document_fix_compatible
  class Rule_L040(Rule_L010):
      """Inconsistent capitalisation of boolean/null literal.
  
      **Anti-pattern**
  
      In this example, ``null`` and ``false`` are in lower-case whereas ``TRUE`` is in
      upper-case.
  
      .. code-block:: sql
  
          select
              a,
              null,
              TRUE,
              false
          from foo
  
      **Best practice**
  
      Ensure all literal ``null``/``true``/``false`` literals are consistently
      upper or lower case
  
      .. code-block:: sql
  
          select
              a,
              NULL,
              TRUE,
              FALSE
          from foo
  
          -- Also good
  
          select
              a,
              null,
              true,
              false
          from foo
  
      """
  
      _target_elems: List[Tuple[str, str]] = [
          ("name", "null_literal"),
          ("name", "boolean_literal"),
      ]
      _exclude_elements: List[Tuple[str, str]] = []
      _description_elem = "Boolean/null literals"
  