parameters: (value, fail_on_errors=True, preserve_none=False)
docstring: Parses a string representing bool value. If parsing was successful,
         returns True or False. If preserve_none=True, returns True, False,
         or None. If parsing was not successful, raises  ValueError, or, if
         fail_on_errors=False, returns None.
docstring_summary: Parses a string representing bool value. If parsing was successful,
         returns True or False. If preserve_none=True, returns True, False,
         or None. If parsing was not successful, raises  ValueError, or, if
         fail_on_errors=False, returns None.
docstring_tokens: Parses a string representing bool value . If parsing was successful returns True or False . If preserve_none = True returns True False or None . If parsing was not successful raises ValueError or if fail_on_errors = False returns None .
function: def parseBoolValue(value, fail_on_errors=True, preserve_none=False):
      """Parses a string representing bool value. If parsing was successful,
         returns True or False. If preserve_none=True, returns True, False,
         or None. If parsing was not successful, raises  ValueError, or, if
         fail_on_errors=False, returns None."""
      if not isinstance(value, string_type):
          if preserve_none and value is None:
              return value
          return bool(value)
      elif preserve_none and value.lower() == 'none':
          return None
      elif value.lower() in ('true', 'yes', 'y', 'on', '1'):
          return True
      elif value.lower() in ('false', 'no', 'n', 'off', '0', 'none'):
          return False
      elif fail_on_errors:
          raise ValueError('Cannot parse bool value: %r' % value)
function_tokens: def parseBoolValue ( value , fail_on_errors = True , preserve_none = False ) : if not isinstance ( value , string_type ) : if preserve_none and value is None : return value return bool ( value ) elif preserve_none and value . lower ( ) == 'none' : return None elif value . lower ( ) in ( 'true' , 'yes' , 'y' , 'on' , '1' ) : return True elif value . lower ( ) in ( 'false' , 'no' , 'n' , 'off' , '0' , 'none' ) : return False elif fail_on_errors : raise ValueError ( 'Cannot parse bool value: %r' % value )