Log Message:
py-pyparsing: updated to 2.4.2

Version 2.4.2:

- Updated the shorthand notation that has been added for repetition
  expressions: expr[min, max], with '...' valid as a min or max value:
     - expr[...] and expr[0, ...] are equivalent to ZeroOrMore(expr)
     - expr[1, ...] is equivalent to OneOrMore(expr)
     - expr[n, ...] or expr[n,] is equivalent
          to expr*n + ZeroOrMore(expr)
          (read as "n or more instances of expr")
     - expr[..., n] is equivalent to expr*(0, n)
     - expr[m, n] is equivalent to expr*(m, n)
  Note that expr[..., n] and expr[m, n] do not raise an exception
  if more than n exprs exist in the input stream.  If this
  behavior is desired, then write expr[..., n] + ~expr.

  Better interpretation of [...] as ZeroOrMore raised by crowsonkb,
  thanks for keeping me in line!

  If upgrading from 2.4.1 or 2.4.1.1 and you have used `expr[...]`
  for `OneOrMore(expr)`, it must be updated to `expr[1, ...]`.

- The defaults on all the `__diag__` switches have been set to False,
  to avoid getting alarming warnings. To use these diagnostics, set
  them to True after importing pyparsing.

  Example:
      import pyparsing as pp
      pp.__diag__.warn_multiple_tokens_in_named_alternation = True

- Fixed bug introduced by the use of __getitem__ for repetition,
  overlooking Python's legacy implementation of iteration
  by sequentially calling __getitem__ with increasing numbers until
  getting an IndexError. Found during investigation of problem
  reported by murlock, merci!