logilab-astng #20759 crash on pyreverse UNARY_OP_METHOD KeyError '~' [validation pending]

Following code will reproduce the crash:

import pyparsing as pyp

class MyClass(MyBase):
  def xyz(self):
    rbrace = pyp.Literal("}").suppress()
    stmt = (~rbrace + keyword + ~lbrace)
prioritynormal
typebug
done in0.20.0
load0.100
load left0.000
closed by<not specified>