class_docstr: Support for `Blaze <blaze.pydata.org>`_ ``Data`` objects.
  
  Only numeric indices to columns are supported.
  
  Note:
  
    - The ``dataname`` parameter is a blaze ``Data`` object
  
    - A negative value in any of the parameters for the Data lines
      indicates it's not present in the DataFrame
      it is
class_docstr_tok: ["Support","for","`","Blaze","<","blaze.pydata.org",">","`","_","``","Data","``","objects",".","Only","numeric","indices","to","columns","are","supported",".","Note",":","-","The","``","dataname","``","parameter","is","a","blaze","``","Data","``","object","-","A","negative","value","in","any","of","the","parameters","for","the","Data","lines","indicates","it","'s","not","present","in","the","DataFrame","it","is"]
code: def start(self):
      super(BlazeData, self).start()
  
      # reset the iterator on each start
      self._rows = iter(self.p.dataname)
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  from backtrader import date2num
  import backtrader.feed
label_desc: Use image node_id 1 for calling the BlazeData obj's underlying member method code with example usage: obj.start() without return types