docstr: Returns the fullname of a given extension name.
  
  Adds the `package.` prefix
docstr_tok: ["Returns","the","fullname","of","a","given","extension","name",".","Adds","the","`","package.","`","prefix"]
code: def get_ext_fullname(self, ext_name):
      """Returns the fullname of a given extension name.
  
      Adds the `package.` prefix"""
      if self.package is None:
          return ext_name
      else:
          return self.package + "." + ext_name
  
imports: import contextlib
  import os
  import re
  import sys
  from ..core import Command
  from ..errors import DistutilsOptionError, DistutilsSetupError, CCompilerError, DistutilsError, CompileError, DistutilsPlatformError
  from ..sysconfig import customize_compiler, get_python_version
  from ..sysconfig import get_config_h_filename
  from .._modified import newer_group
  from ..extension import Extension
  from ..util import get_platform
  from distutils._log import log
  from .None import py37compat
  from site import USER_BASE
label_desc: Use image node_id 15 for calling the build_ext obj's underlying member method code with example usage: obj.get_ext_fullname(ext_name) and returns: ext_name, unknown