class_docstr: A tuple of `InfDim`s.
  
  This is intended to be attached to each parameter tensor `p` as `p.infshape`.
code: def ninf(self):
      return sum(1 for dim in self if dim.isinf())
  
imports: from copy import copy
label_desc: Use image node_id 4 for calling the InfShape obj's underlying member method code with example usage: obj.ninf() and returns: sum