class_docstr: This is the base class for *Sizers*. Any *sizer* should subclass this
  and override the ``_getsizing`` method
  
  Member Attribs:
  
    - ``strategy``: will be set by the strategy in which the sizer is working
  
      Gives access to the entire api of the strategy, for example if the
      actual data position would be needed in ``_getsizing``::
  
         position = self.strategy.getposition(data)
  
    - ``broker``: will be set by the strategy in which the sizer is working
  
      Gives access to information some complex sizers may need like portfolio
      value, ..
code: def set(self, strategy, broker):
      self.strategy = strategy
      self.broker = broker
  
file_path: backtrader/backtrader/sizer.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  from .utils.py3 import with_metaclass
  from .metabase import MetaParams
label_desc: Use image node_id 3 for calling the Sizer obj's underlying member method code with example usage: obj.set(strategy, broker) without return types