class_docstr: Class to manipulate the TextGrid format used by Praat.
  Separates each tier within this file into its own Tier
  object.  Each TextGrid object has
  a number of tiers (size), xmin, xmax, a text type to help
  with the different styles of TextGrid format, and tiers with their
  own attributes.
class_docstr_tok: ["Class","to","manipulate","the","TextGrid","format","used","by","Praat",".","Separates","each","tier","within","this","file","into","its","own","Tier","object",".","Each","TextGrid","object","has","a","number","of","tiers","(","size",")",",","xmin",",","xmax",",","a","text","type","to","help","with","the","different","styles","of","TextGrid","format",",","and","tiers","with","their","own","attributes","."]
docstr: Splits the textgrid file into substrings corresponding to tiers. 
docstr_tok: ["Splits","the","textgrid","file","into","substrings","corresponding","to","tiers","."]
code: def _find_tiers(self):
      """
      Splits the textgrid file into substrings corresponding to tiers.
      """
  
      if self.text_type == "ooTextFile":
          m = OOTEXTFILE
          header = " +item \["
      elif self.text_type == "ChronTextFile":
          m = CHRONTEXTFILE
          header = '"\S+" ".*" \d+\.?\d* \d+\.?\d*'
      elif self.text_type == "OldooTextFile":
          m = OLDOOTEXTFILE
          header = '".*"[\r\n]+".*"'
  
      file_info = m.findall(self.read_file)[0]
      self.xmin = float(file_info[0])
      self.xmax = float(file_info[1])
      self.t_time = self.xmax - self.xmin
      self.size = int(file_info[2])
      tiers = self._load_tiers(header)
      return tiers
  
imports: import sys
  import re
label_desc: Use image node_id 7 for calling the TextGrid obj's underlying member method code with example usage: obj._find_tiers() and returns: tiers