class_docstr: SpecialSymbol(sym) is an RE which matches the special input
  symbol |sym|, which is one of BOL, EOL or EOF.
class_docstr_tok: ["SpecialSymbol","(","sym",")","is","an","RE","which","matches","the","special","input","symbol","|sym|",",","which","is","one","of","BOL",",","EOL","or","EOF","."]
code: def __init__(self, sym):
      self.sym = sym
  
imports: from __future__ import absolute_import
  import types
  from .None import Errors
label_desc: Use image node_id 1 to create a new SpecialSymbol object from inherited base classes: RE with example: obj = SpecialSymbol(sym)