class_docstr: Methods in this class recursively traverse an AST and
  output source code for the abstract syntax; original formatting
  is disregarged.
docstr: Print ':', and increase the indentation.
docstr_tok: ["Print","'",":","'",",","and","increase","the","indentation","."]
code: def _enter(self):
      "Print ':', and increase the indentation."
      self._write(": ")
      self._indent += 1
  
imports: import sys
  from compiler.ast import Const, Name, Tuple, Div, Mul, Sub, Add
label_desc: Use image node_id 4 for calling the UnparseCompilerAst obj's underlying member method code with example usage: obj._enter() without return types