old_contents: PROPERTIES = {
  
      # common.Property.name_id
      'air_temperature': {
  
          # dictionary of observation providers of given property
          # mandatory, at least one provider must be specified
          'observation_providers': {
  
              # path to Django model
              # the model must be subclass of common.AbstractObservation
              'apps.processing.ala.models.Observation': {
  
                  # currently empty, will be used later for optional filter
              },
          },
  
          # mandatory, number of seconds
          'value_frequency': 3600,
  
          # mandatory, name_id of common.Process
          'process': 'avg_hour',
      },
  
      'ground_air_temperature': {
          'observation_providers': {
              'apps.processing.ala.models.Observation': {},
          },
          'value_frequency': 3600,
          'process': 'avg_hour',
      },
  
  }
new_contents: PROPERTIES = {
  
      # common.Property.name_id
      'air_temperature': {
  
          # dictionary of observation providers of given property
          # mandatory, at least one provider must be specified
          'observation_providers': {
  
              # path to Django model
              # the model must be subclass of common.AbstractObservation
              'apps.processing.ala.models.Observation': {
  
                  # mandatory, name_id of common.Process
                  'process': 'avg_hour',
              },
          },
  
          # mandatory, number of seconds
          'value_frequency': 3600,
  
          # mandatory, name_id of common.Process
          'process': 'avg_hour',
      },
  
      'ground_air_temperature': {
          'observation_providers': {
              'apps.processing.ala.models.Observation': {
                  'process': 'avg_hour',
              },
          },
          'value_frequency': 3600,
          'process': 'avg_hour',
      },
  
  }
  
subject: Move process filter to observation_provider