class_docstr: A tuple of `InfDim`s.
  
  This is intended to be attached to each parameter tensor `p` as `p.infshape`.
code: def width_mult(self):
      if self.main is not None:
          return self.main.width_mult()
      return 1
  
imports: from copy import copy
label_desc: Use image node_id 5 for calling the InfShape obj's underlying member method code with example usage: obj.width_mult() and returns: int, self