old_contents: """An abstract base class for all Dakota variable types."""
  
  from abc import ABCMeta, abstractmethod
  
  
  class VariableBase(object):
  
      """Describe features common to all Dakota variable types."""
  
      __metaclass__ = ABCMeta
  
      @abstractmethod
      def __init__(self,
                   variables='continuous_design',
                   descriptors=(),
                   **kwargs):
          """Create a set of default experiment parameters."""
          self.variables = variables
          self._descriptors = descriptors
  
      @property
      def descriptors(self):
          """Labels attached to Dakota variables."""
          return self._descriptors
  
      @descriptors.setter
      def descriptors(self, value):
          """Set labels for Dakota variables.
  
          Parameters
          ----------
          value : str or list or tuple of str
            The new variables labels.
  
          """
          if type(value) is str:
              value = (value,)
          if not isinstance(value, (tuple, list)):
              raise TypeError("Descriptors must be a string, tuple or list")
          self._descriptors = value
  
      def __str__(self):
          """Define the variables block of a Dakota input file."""
          s = 'variables\n' \
              + ' {0} = {1}\n'.format(self.variables,
                                      len(self.descriptors))
          s += '    descriptors ='
          for vd in self.descriptors:
              s += ' {!r}'.format(vd)
          return(s)
  
new_contents: """An abstract base class for all Dakota variable types."""
  
  from abc import ABCMeta, abstractmethod
  
  
  class VariableBase(object):
  
      """Describe features common to all Dakota variable types."""
  
      __metaclass__ = ABCMeta
  
      @abstractmethod
      def __init__(self,
                   variables='continuous_design',
                   descriptors=()):
          """Create a set of default experiment parameters."""
          self.variables = variables
          self._descriptors = descriptors
  
      @property
      def descriptors(self):
          """Labels attached to Dakota variables."""
          return self._descriptors
  
      @descriptors.setter
      def descriptors(self, value):
          """Set labels for Dakota variables.
  
          Parameters
          ----------
          value : str or list or tuple of str
            The new variables labels.
  
          """
          if type(value) is str:
              value = (value,)
          if not isinstance(value, (tuple, list)):
              raise TypeError("Descriptors must be a string, tuple or list")
          self._descriptors = value
  
      def __str__(self):
          """Define the variables block of a Dakota input file."""
          s = 'variables\n' \
              + ' {0} = {1}\n'.format(self.variables,
                                      len(self.descriptors))
          s += '    descriptors ='
          for vd in self.descriptors:
              s += ' {!r}'.format(vd)
          return(s)
  
subject: Remove unneeded kwargs argument