class_docstr: An operator stream that applies a specific function to the values of
  a given stream.
  
  Parameters
  ----------
  func : `Callable[[T], ...]`
      A function to be applied to the values of a stream.
  dtype : str, optional
      The data type of the values after function is applied.
class_docstr_tok: ["An","operator","stream","that","applies","a","specific","function","to","the","values","of","a","given","stream",".","Parameters","--","--","--","--","--","func",":","`","Callable","[","[","T","]",",","...","]","`","A","function","to","be","applied","to","the","values","of","a","stream",".","dtype",":","str",",","optional","The","data","type","of","the","values","after","function","is","applied","."]
code: def forward(self) -> K:
      node = self.inputs[0]
      return self.func(node.value)
  
imports: from typing import Callable, TypeVar
  import numpy
  from tensortrade.feed.core.base import Stream, T
label_desc: Use image node_id 2 for calling the Apply obj's underlying member method code with example usage: obj.forward() and returns: self