text: '''
  custom exceptions for IPySigma application
  
  '''
  
  class IPySigmaBaseException(Exception):
      ''' 
      exception base class for IPySigmaPackage
      '''
      pass
  
  
  class IPySigmaAddOnException(IPySigmaBaseException):
      '''
      exception base class for sigma_add_on module
      '''
      pass
  
  
  class IPySigmaCoreException(IPySigmaBaseException):
      '''
      exception base class for SigmaCore module
      '''
      pass
  
  
  class IPySigmaGraphNodeIndexError(IPySigmaAddOnException, IndexError):
      '''
      exception thrown when graphs are empty
      '''
      pass
  
  class IPySigmaGraphEdgeIndexError(IPySigmaAddOnException, IndexError):
      '''
      exception thrown when graphs are empty
      '''
      pass
  
  
  class IPySigmaGraphDataFrameValueError(IPySigmaAddOnException, ValueError):
      '''
      exception thrown when build_pandas_df method returns empty dfs
      '''
      pass
  
  class IPySigmaGraphJSONValueError(IPySigmaAddOnException, ValueError):
      '''
      exception thrown if JSON dict is empty
      '''
      pass
  
  
  class IPySigmaNodeTypeError(IPySigmaAddOnException):
      '''
      exception thrown if 'node_type' field has not been assigned by user to node attributes
      '''
  
  class IPySigmaLabelError(IPySigmaAddOnException):
      '''
      exception thrown if 'label' field has not been assigned by the user to node attributes
      '''