code: def _print_Ei(self, expr):
      return self._print_math_func(expr)
  
imports: from itertools import chain
  from sympy.codegen.ast import Type, none
  from .codeprinter import requires
  from .c import C89CodePrinter, C99CodePrinter
  from sympy.printing.codeprinter import cxxcode
label_desc: Use image node_id 2 for calling the CXX17CodePrinter obj's underlying member method code with example usage: obj._print_Ei(expr) and returns: self