old_contents: from django.conf import settings
  
  from netaddr import mac_eui48, mac_unix
  
  import importlib
  
  def default_dialect(eui_obj=None):
      # Check to see if a default dialect class has been specified in settings, 
      # using 'module.dialect_cls' string and use importlib and getattr to retrieve dialect class. 'module' is the module and 
      # 'dialect_cls' is the class name of the custom dialect. The dialect must either be defined or imported by the module's 
      # __init__.py if the module is a package.
      if hasattr(settings, 'MACADDRESS_DEFAULT_DIALECT'):
          module, dialect_cls = settings.MACADDRESS_DEFAULT_DIALECT.split('.')
          dialect = getattr(importlib.import_module(module), dialect_cls, mac_eui48)
          return dialect
      else:
          if eui_obj:
              return eui_obj.dialect
          else:
              return mac_eui48
  
  def format_mac(eui_obj, dialect):
      # Format a EUI instance as a string using the supplied dialect class, allowing custom string classes by 
      # passing directly or as a string, a la 'module.dialect_cls', where 'module' is the module and 'dialect_cls'
      # is the class name of the custom dialect. The dialect must either be defined or imported by the module's __init__.py if 
      # the module is a package.
      if not isinstance(dialect, mac_eui48):
          if isinstance(dialect, str):
              module, dialect_cls = dialect.split('.')
              dialect = getattr(importlib.import_module(module), dialect_cls)
      eui_obj.dialect = dialect
      return str(eui_obj)
  
  class mac_linux(mac_unix):
      """MAC format with zero-padded all upper-case hex and colon separated"""
      word_fmt = '%.2X'
new_contents: from django.conf import settings
  
  from netaddr import mac_unix
  
  import importlib
  
  class mac_linux(mac_unix):
      """MAC format with zero-padded all upper-case hex and colon separated"""
      word_fmt = '%.2X'
  
  def default_dialect(eui_obj=None):
      # Check to see if a default dialect class has been specified in settings, 
      # using 'module.dialect_cls' string and use importlib and getattr to retrieve dialect class. 'module' is the module and 
      # 'dialect_cls' is the class name of the custom dialect. The dialect must either be defined or imported by the module's 
      # __init__.py if the module is a package.
      if hasattr(settings, 'MACADDRESS_DEFAULT_DIALECT'):
          module, dialect_cls = settings.MACADDRESS_DEFAULT_DIALECT.split('.')
          dialect = getattr(importlib.import_module(module), dialect_cls, mac_linux)
          return dialect
      else:
          if eui_obj:
              return eui_obj.dialect
          else:
              return mac_linux
  
  def format_mac(eui_obj, dialect):
      # Format a EUI instance as a string using the supplied dialect class, allowing custom string classes by 
      # passing directly or as a string, a la 'module.dialect_cls', where 'module' is the module and 'dialect_cls'
      # is the class name of the custom dialect. The dialect must either be defined or imported by the module's __init__.py if 
      # the module is a package.
      if not isinstance(dialect, mac_eui48):
          if isinstance(dialect, str):
              module, dialect_cls = dialect.split('.')
              dialect = getattr(importlib.import_module(module), dialect_cls)
      eui_obj.dialect = dialect
      return str(eui_obj)
subject: Tweak to change default dialec to mac_linux.