code: def _compile_dialect(self, execute_observed):
      if self.dialect == "default":
          dialect = DefaultDialect()
          # this is currently what tests are expecting
          # dialect.supports_default_values = True
          dialect.supports_default_metavalue = True
  
          if self.enable_returning:
              dialect.insert_returning = (
                  dialect.update_returning
              ) = dialect.delete_returning = True
              dialect.use_insertmanyvalues = True
              dialect.supports_multivalues_insert = True
              dialect.update_returning_multifrom = True
              dialect.delete_returning_multifrom = True
              # dialect.favor_returning_over_lastrowid = True
              # dialect.insert_null_pk_still_autoincrements = True
  
              # this is calculated but we need it to be True for this
              # to look like all the current RETURNING dialects
              assert dialect.insert_executemany_returning
  
          return dialect
      else:
          return url.URL.create(self.dialect).get_dialect()()
  
imports: from __future__ import annotations
  import collections
  import contextlib
  import itertools
  import re
  from ..None import event
  from ..engine import url
  from ..engine.default import DefaultDialect
  from ..schema import BaseDDLElement
label_desc: Use image node_id 3 for calling the CompiledSQL obj's underlying member method code with example usage: obj._compile_dialect(execute_observed) and returns: dialect, url