code: def _get_env(environment, name):
      value = environment.get(name, _undefined)
  
      if value is _undefined:
          raise UndefinedEnvironmentName(
              "{0!r} does not exist in evaluation environment.".format(
                  name
              )
          )
  
      return value
  
imports: from __future__ import absolute_import, division, print_function
  import operator
  import os
  import platform
  import sys
  from pkg_resources.extern.pyparsing import ParseException, ParseResults, stringStart, stringEnd
  from pkg_resources.extern.pyparsing import ZeroOrMore, Group, Forward, QuotedString
  from pkg_resources.extern.pyparsing import Literal
  from ._compat import string_types
  from .specifiers import Specifier, InvalidSpecifier
label_desc: Use image node_id 4 for calling a global function with example usage: _get_env(environment, name) and returns: value