class_docstr: Multiple proximal operator. This allows to apply sequentially a list
  of proximal operators. This is convenient when one wants to apply different
  proximal operators on different parts of a vector.
  
  Parameters
  ----------
  proxs : `tuple` of `Prox`
      A tuple of prox operators to be applied successively.
  
  Attributes
  ----------
  dtype : `{'float64', 'float32'}`
      Type of the arrays used.
code: def astype(self, dtype_or_object_with_dtype):
      raise NotImplementedError(
          "This type requires each Prox to their 'astype' called (for now)"
      )
  
file_path: tick/tick/prox/prox_multi.py
imports: import numpy
  from .base import Prox
  from .build.prox import ProxMultiDouble
  from .build.prox import ProxMultiFloat
  from tick.prox import ProxZero
label_desc: Use image node_id 5 for calling the ProxMulti obj's underlying member method code with example usage: obj.astype(dtype_or_object_with_dtype) without return types