class_docstr: This sizer simply returns a fixed size for any operation
  
  Params:
    - ``perc`` (default: ``0.20``) Perc of cash to allocate for operation
class_docstr_tok: ["This","sizer","simply","returns","a","fixed","size","for","any","operation","Params",":","-","``","perc","``","(","default",":","``","0.20","``",")","Perc","of","cash","to","allocate","for","operation"]
code: def _getsizing(self, comminfo, cash, data, isbuy):
      cashtouse = self.p.perc * cash
      if BTVERSION > (1, 7, 1, 93):
          size = comminfo.getsize(data.close[0], cashtouse)
      else:
          size = cashtouse // data.close[0]
      return size
  
file_path: backtrader/samples/macd-settings/macd-settings.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import argparse
  import datetime
  import random
  import backtrader
label_desc: Use image node_id 1 for calling the FixedPerc obj's underlying member method code with example usage: obj._getsizing(comminfo, cash, data, isbuy) and returns: size