class_docstr: This sizer returns the needes fixed size to reverse an open position or
  the fixed size to open one
  
    - To open a position: return the param ``stake``
  
    - To reverse a position: return 2 * ``stake``
  
  Params:
    - ``stake`` (default: ``1``)
class_docstr_tok: ["This","sizer","returns","the","needes","fixed","size","to","reverse","an","open","position","or","the","fixed","size","to","open","one","-","To","open","a","position",":","return","the","param","``","stake","``","-","To","reverse","a","position",":","return","2","*","``","stake","``","Params",":","-","``","stake","``","(","default",":","``","1","``",")"]
code: def _getsizing(self, comminfo, cash, data, isbuy):
      position = self.strategy.getposition(data)
      size = self.p.stake * (1 + (position.size != 0))
      return size
  
file_path: backtrader/backtrader/sizers/fixedsize.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import backtrader
label_desc: Use image node_id 1 for calling the FixedReverser obj's underlying member method code with example usage: obj._getsizing(comminfo, cash, data, isbuy) and returns: size