old_contents: import datetime
  from decimal import Decimal
  import types
  import six
  
  
  def is_protected_type(obj):
      """Determine if the object instance is of a protected type.
  
      Objects of protected types are preserved as-is when passed to
      force_unicode(strings_only=True).
      """
      return isinstance(obj, (
          types.NoneType,
          int, long,
          datetime.datetime, datetime.date, datetime.time,
          float, Decimal)
      )
  
  
  def force_unicode(s, encoding='utf-8', strings_only=False, errors='strict'):
      """
      Similar to smart_text, except that lazy instances are resolved to
      strings, rather than kept as lazy objects.
  
      If strings_only is True, don't convert (some) non-string-like objects.
      """
      # Handle the common case first, saves 30-40% when s is an instance of
      # six.text_type. This function gets called often in that setting.
      if isinstance(s, six.text_type):
          return s
      if strings_only and is_protected_type(s):
          return s
      try:
          if not isinstance(s, six.string_types):
              if hasattr(s, '__unicode__'):
                  s = s.__unicode__()
              else:
                  if six.PY3:
                      if isinstance(s, bytes):
                          s = six.text_type(s, encoding, errors)
                      else:
                          s = six.text_type(s)
                  else:
                      s = six.text_type(bytes(s), encoding, errors)
          else:
              # Note: We use .decode() here, instead of six.text_type(s, encoding,
              # errors), so that if s is a SafeBytes, it ends up being a
              # SafeText at the end.
              s = s.decode(encoding, errors)
      except UnicodeDecodeError as e:
          if not isinstance(s, Exception):
              raise DjangoUnicodeDecodeError(s, *e.args)
          else:
              # If we get to here, the caller has passed in an Exception
              # subclass populated with non-ASCII bytestring data without a
              # working unicode method. Try to handle this without raising a
              # further exception by individually forcing the exception args
              # to unicode.
              s = ' '.join([force_text(arg, encoding, strings_only,
                      errors) for arg in s])
      return s
  
new_contents: import datetime
  from decimal import Decimal
  import types
  import six
  
  
  def is_protected_type(obj):
      """Determine if the object instance is of a protected type.
  
      Objects of protected types are preserved as-is when passed to
      force_unicode(strings_only=True).
      """
      return isinstance(obj, (
          types.NoneType,
          int, long,
          datetime.datetime, datetime.date, datetime.time,
          float, Decimal)
      )
  
  
  def force_unicode(s, encoding='utf-8', strings_only=False, errors='strict'):
      """
      Similar to smart_text, except that lazy instances are resolved to
      strings, rather than kept as lazy objects.
  
      If strings_only is True, don't convert (some) non-string-like objects.
      """
      # Handle the common case first, saves 30-40% when s is an instance of
      # six.text_type. This function gets called often in that setting.
      if isinstance(s, six.text_type):
          return s
      if strings_only and is_protected_type(s):
          return s
      try:
          if not isinstance(s, six.string_types):
              if hasattr(s, '__unicode__'):
                  s = s.__unicode__()
              else:
                  if six.PY3:
                      if isinstance(s, bytes):
                          s = six.text_type(s, encoding, errors)
                      else:
                          s = six.text_type(s)
                  else:
                      s = six.text_type(bytes(s), encoding, errors)
          else:
              # Note: We use .decode() here, instead of six.text_type(s, encoding,
              # errors), so that if s is a SafeBytes, it ends up being a
              # SafeText at the end.
              s = s.decode(encoding, errors)
      except UnicodeDecodeError as e:
          if not isinstance(s, Exception):
              raise UnicodeDecodeError(*e.args)
          else:
              # If we get to here, the caller has passed in an Exception
              # subclass populated with non-ASCII bytestring data without a
              # working unicode method. Try to handle this without raising a
              # further exception by individually forcing the exception args
              # to unicode.
              s = ' '.join([force_text(arg, encoding, strings_only,
                            errors) for arg in s])
      return s
  
subject: update as per #101