old_contents: # dialects/__init__.py
  # Copyright (C) 2005-2020 the SQLAlchemy authors and contributors
  # <see AUTHORS file>
  #
  # This module is part of SQLAlchemy and is released under
  # the MIT License: http://www.opensource.org/licenses/mit-license.php
  
  __all__ = (
      "firebird",
      "mssql",
      "mysql",
      "oracle",
      "postgresql",
      "sqlite",
      "sybase",
  )
  
  from .. import util
  
  
  def _auto_fn(name):
      """default dialect importer.
  
      plugs into the :class:`.PluginLoader`
      as a first-hit system.
  
      """
      if "." in name:
          dialect, driver = name.split(".")
      else:
          dialect = name
          driver = "base"
  
      try:
          if dialect == "firebird":
              try:
                  module = __import__("sqlalchemy_firebird")
                  dialect = "dialect"
              except:
                  module = __import__("sqlalchemy.dialects.firebird").dialects
          else:
              module = __import__("sqlalchemy.dialects.%s" % (dialect,)).dialects
      except ImportError:
          return None
  
      module = getattr(module, dialect)
      if hasattr(module, driver):
          module = getattr(module, driver)
          return lambda: module.dialect
      else:
          return None
  
  
  registry = util.PluginLoader("sqlalchemy.dialects", auto_fn=_auto_fn)
  
  plugins = util.PluginLoader("sqlalchemy.plugins")
  
new_contents: # dialects/__init__.py
  # Copyright (C) 2005-2020 the SQLAlchemy authors and contributors
  # <see AUTHORS file>
  #
  # This module is part of SQLAlchemy and is released under
  # the MIT License: http://www.opensource.org/licenses/mit-license.php
  
  __all__ = (
      "firebird",
      "mssql",
      "mysql",
      "oracle",
      "postgresql",
      "sqlite",
      "sybase",
  )
  
  from .. import util
  
  
  def _auto_fn(name):
      """default dialect importer.
  
      plugs into the :class:`.PluginLoader`
      as a first-hit system.
  
      """
      if "." in name:
          dialect, driver = name.split(".")
      else:
          dialect = name
          driver = "base"
  
      try:
          if dialect == "firebird":
              try:
                  module = __import__("sqlalchemy_firebird")
              except ImportError:
                  module = __import__("sqlalchemy.dialects.firebird").dialects
                  module = getattr(module, dialect)
          elif dialect == "sybase":
              try:
                  module = __import__("sqlalchemy_sybase")
              except ImportError:
                  module = __import__("sqlalchemy.dialects.sybase").dialects
                  module = getattr(module, dialect)
          else:
              module = __import__("sqlalchemy.dialects.%s" % (dialect,)).dialects
              module = getattr(module, dialect)
      except ImportError:
          return None
  
      if hasattr(module, driver):
          module = getattr(module, driver)
          return lambda: module.dialect
      else:
          return None
  
  
  registry = util.PluginLoader("sqlalchemy.dialects", auto_fn=_auto_fn)
  
  plugins = util.PluginLoader("sqlalchemy.plugins")
  
subject: Load external firebird or sybase dialect if available