docs: def aliased_as(self, name):
          """
          Create an alias of this stream.
  
          Returns an alias of this stream with name `name`.
          When invocation of an SPL operator requires an
          :py:class:`~streamsx.spl.op.Expression` against
          an input port this can be used to ensure expression
          matches the input port alias regardless of the name
          of the actual stream.
  
          Example use where the filter expression for a ``Filter`` SPL operator
          uses ``IN`` to access input tuple attribute ``seq``::
  
              s = ...
              s = s.aliased_as('IN')
  
              params =  {'filter': op.Expression.expression('IN.seq % 4ul == 0ul')}
              f = op.Map('spl.relational::Filter', stream, params = params)
  
          Args:
              name(str): Name for returned stream.
  
          Returns:
              Stream: Alias of this stream with ``name`` equal to `name`.
          
          .. versionadded:: 1.9
          """
          stream = copy.copy(self)
          stream._alias = name
          return stream