old_contents: from ConfigParser import ConfigParser as DefaultConfigParser
  
  
  class ConfigParser(DefaultConfigParser):
      """
      Adaptation of python's ConfigParser.ConfigParser removing some limitations
      related to sections called 'default'.
      """
  
      def set(self, section, option, value=None):
          """Set an option."""
          try:
              sectdict = self._sections[section]
          except KeyError:
              raise NoSectionError(section)
          sectdict[self.optionxform(option)] = value
  
      def add_section(self, section):
          """Create a new section in the configuration.
  
          Raise DuplicateSectionError if a section by the specified name
          already exists.
          """
          if section in self._sections:
              raise DuplicateSectionError(section)
          self._sections[section] = self._dict()
  
new_contents: try:
      from ConfigParser import ConfigParser as DefaultConfigParser
  except ImportError:
      from configparser import ConfigParser as DefaultConfigParser
  
  
  class ConfigParser(DefaultConfigParser):
      """
      Adaptation of python's ConfigParser.ConfigParser removing some limitations
      related to sections called 'default'.
      """
  
      def set(self, section, option, value=None):
          """Set an option."""
          try:
              sectdict = self._sections[section]
          except KeyError:
              raise NoSectionError(section)
          sectdict[self.optionxform(option)] = value
  
      def add_section(self, section):
          """Create a new section in the configuration.
  
          Raise DuplicateSectionError if a section by the specified name
          already exists.
          """
          if section in self._sections:
              raise DuplicateSectionError(section)
          self._sections[section] = self._dict()
  
subject: Fix tests