code: def ascii(expr, cache=None, **settings):
      
      try:
          if cache is None and len(settings) == 0:
              return ascii.printer.doprint(expr)
          else:
              printer = ascii._printer_cls(cache, settings)
              return printer.doprint(expr)
      except AttributeError:
          # init_printing was not called. Setting up defaults
          ascii._printer_cls = QnetAsciiPrinter
          ascii.printer = ascii._printer_cls()
          return ascii(expr, cache, **settings)
docs: Return an ASCII representation of the given object / expression
  
      Args:
          expr: Expression to print
          cache (dict or None): dictionary to use for caching
          show_hs_label (bool or str): Whether to a label for the Hilbert space
              of `expr`. By default (``show_hs_label=True``), the label is shown
              as a superscript. It can be shown as a subscript with
              ``show_hs_label='subscript'`` or suppressed entirely
              (``show_hs_label=False``)
          sig_as_ketbra (bool): Whether to render instances of
              :class:`.LocalSigma` as a ket-bra (default), or as an operator
              symbol
  
      Examples:
  
          >>> A = OperatorSymbol('A', hs=1); B = OperatorSymbol('B', hs=1)
          >>> ascii(A + B)
          'A^(1) + B^(1)'
          >>> ascii(A + B, cache={A: 'A', B: 'B'})
          'A + B'
          >>> ascii(A + B, show_hs_label='subscript')
          'A_(1) + B_(1)'
          >>> ascii(A + B, show_hs_label=False)
          'A + B'
          >>> ascii(LocalSigma(0, 1, hs=1))
          '|0><1|^(1)'
          >>> ascii(LocalSigma(0, 1, hs=1), sig_as_ketbra=False)
          'sigma_0,1^(1)'
  
      Note that the accepted parameters and their default values may be changed
      through :func:`init_printing` or :func:`configure_printing`