text: 
  class BabbageException(Exception):
      """ A stub exception class for all errors stemming from babbage calls. """
      http_equiv = 500
  
      def __init__(self, message, **context):
          self.message = message
          self.context = context
          super(BabbageException, self).__init__(message)
  
  
  class BindingException(BabbageException):
      """ A class of exceptions that occur when the bindings between the logical
      model and the physical schema aren't valid. """
  
      def __init__(self, message, table=None, column=None):
          super(BindingException, self).__init__(message, table=table,
                                                 column=column)
  
  
  class QueryException(BabbageException):
      """ A class of exceptions that occur when an invalid query is submitted
      or the query cannot be executed. """
      http_equiv = 400
  