class_docstr: A grammar based chunk parser.  ``chunk.RegexpParser`` uses a set of
  regular expression patterns to specify the behavior of the parser.
  The chunking of the text is encoded using a ``ChunkString``, and
  each rule acts by modifying the chunking in the ``ChunkString``.
  The rules are all implemented using regular expression matching
  and substitution.
  
  A grammar contains one or more clauses in the following form::
  
   NP:
     {<DT|JJ>}          # chunk determiners and adjectives
     }<[\.VI].*>+{      # strip any tag beginning with V, I, or .
     <.*>}{<DT>         # split a chunk at a determiner
     <DT|JJ>{}<NN.*>    # merge chunk ending with det/adj
                        # with one starting with a noun
  
  The patterns of a clause are executed in order.  An earlier
  pattern may introduce a chunk boundary that prevents a later
  pattern from executing.  Sometimes an individual pattern will
  match on multiple, overlapping extents of the input.  As with
  regular expression substitution more generally, the chunker will
  identify the first match possible, then continue looking for matches
  after this one has ended.
  
  The clauses of a grammar are also executed in order.  A cascaded
  chunk parser is one having more than one clause.  The maximum depth
  of a parse tree created by this chunk parser is the same as the
  number of clauses in the grammar.
  
  When tracing is turned on, the comment portion of a line is displayed
  each time the corresponding pattern is applied.
  
  :type _start: str
  :ivar _start: The start symbol of the grammar (the root node of
      resulting trees)
  :type _stages: int
  :ivar _stages: The list of parsing stages corresponding to the grammar
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docstr: :return: a verbose string representation of this
      ``RegexpParser``.
  :rtype: str
docstr_tok: [":","return",":","a","verbose","string","representation","of","this","``","RegexpParser","``",".",":","rtype",":","str"]
code: def __str__(self):
      """
      :return: a verbose string representation of this
          ``RegexpParser``.
      :rtype: str
      """
      s = "chunk.RegexpParser with %d stages:\n" % len(self._stages)
      margin = 0
      for parser in self._stages:
          s += "%s\n" % parser
      return s[:-1]
  
imports: import re
  import regex
  from nltk.chunk.api import ChunkParserI
  from nltk.tree import Tree
label_desc: Use image node_id 6 for calling the RegexpParser obj's underlying member method code with example usage: obj.__str__() and returns: s