class_docstr: Compiles a grammar. This will take the parse tree of a regular expression
  and compile the grammar.
  
  :param root_node: :class~`.regex_parser.Node` instance.
  :param escape_funcs: `dict` mapping variable names to escape callables.
  :param unescape_funcs: `dict` mapping variable names to unescape callables.
docstr: Escape `value` to fit in the place of this variable into the grammar.
docstr_tok: ["Escape","`","value","`","to","fit","in","the","place","of","this","variable","into","the","grammar","."]
code: def escape(self, varname, value):
      """
      Escape `value` to fit in the place of this variable into the grammar.
      """
      f = self.escape_funcs.get(varname)
      return f(value) if f else value
  
imports: from __future__ import unicode_literals
  import re
  from six.moves import range
  from .regex_parser import Any, Sequence, Regex, Variable, Repeat, Lookahead
  from .regex_parser import parse_regex, tokenize_regex
label_desc: Use image node_id 2 for calling the _CompiledGrammar obj's underlying member method code with example usage: obj.escape(varname, value) and returns: unknown