old_contents: 
  import xmltodict
  
  
  class OperationResult:
  
      def __init__(self, response):
          self.response = response
          self.data = xmltodict.parse(response.content)
  
      @property
      def error(self):
          return int(self.error_code) != 0
  
      @property
      def error_code(self):
          return self.data['response']['operation']['result']['error']
  
  
  class Operation(object):
      '''Base class for API operations'''
  
      #: Relative url to the client's ``base_url``. Operation endpoint url
      url = '/cgi-bin/xml-parser.cgi'
  
      #: Operation type (`show`, `config`, etc)
      op_type = 'show'
  
      #: Operation specific data bundle
      op_data = {}
  
      def __init__(self, client):
          self.client = client
  
      def get_base_data(self):
          return {
              'request': {
                  'operation': {
                      '@token': self.get_token(),
                      '@type': self.get_type(),
                  }
              }
          }
  
      def get_data(self, data=None):
          '''
          Merges operation base data structure with operation related one and
          returns the whole bundle which, after serializing to xml can be used
          for operation request.
  
          :param data: Data to merge with operation data
          :type data: dict
  
          :returns: full operation data structure
          '''
          base_data = self.get_base_data()
          op_data = self.get_op_data()
          op_data.update(data if data else {})
          base_data['request']['operation'].update(op_data)
          return base_data
  
      def get_token(self):
          return self.client.token
  
      def get_type(self):
          return self.op_type
  
      def get_op_data(self):
          return self.op_data.copy()
  
      def execute(self, data=None):
          '''
          Execute API request operation with given operation ``data``
  
          :param data: Operation related data pased to ``get_data`` method
          :type data: dict or None
  
          :returns: Parsed API response as dictionary
          '''
          response = self.client._req(
              url=self.url,
              data=xmltodict.unparse(self.get_data(data=data)))
          return OperationResult(response)
  
  
  class ShowEquipmentOp(Operation):
      op_data = {'@entity': 'equipment', 'equipment': None}
  
new_contents: 
  import xmltodict
  
  
  class OperationResult:
  
      def __init__(self, response):
          self.response = response
          self.data = xmltodict.parse(response.content)
  
      @property
      def error(self):
          return int(self.error_code) != 0
  
      @property
      def error_code(self):
          return self.data['response']['operation']['result']['error']
  
  
  class Operation(object):
      '''Base class for API operations'''
  
      #: Relative url to the client's ``base_url``. Operation endpoint url
      url = '/cgi-bin/xml-parser.cgi'
  
      #: Operation type (`show`, `config`, etc)
      op_type = 'show'
  
      #: Operation specific data bundle
      op_data = {}
  
      def __init__(self, client):
          self.client = client
  
      def get_base_data(self):
          return {
              'request': {
                  'operation': {
                      '@token': self.get_token(),
                      '@type': self.get_type(),
                  }
              }
          }
  
      def get_data(self, data=None):
          '''
          Merges operation base data structure with operation related one and
          returns the whole bundle which, after serializing to xml can be used
          for operation request.
  
          :param data: Data to merge with operation data
          :type data: dict
  
          :returns: full operation data structure
          '''
          base_data = self.get_base_data()
          op_data = self.get_op_data()
          op_data.update(data if data else {})
          base_data['request']['operation'].update(op_data)
          return base_data
  
      def get_token(self):
          '''Get token for the operation'''
          return self.client.token
  
      def get_type(self):
          '''Get type of operation. ``show``, ``config`` etc.'''
          return self.op_type
  
      def get_op_data(self):
          '''Returns operation related data bundle'''
          return self.op_data.copy()
  
      def execute(self, data=None):
          '''
          Execute API request operation with given operation ``data``
  
          :param data: Operation related data pased to ``get_data`` method
          :type data: dict or None
  
          :returns: Parsed API response as dictionary
          '''
          response = self.client._req(
              url=self.url,
              data=xmltodict.unparse(self.get_data(data=data)))
          return OperationResult(response)
  
  
  class ShowEquipmentOp(Operation):
      op_data = {'@entity': 'equipment', 'equipment': None}
  
subject: Add some docstrings