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  The input is expected to be in the form reactant>reagent>product. The source

  string would be reactants>reagents and the target string would be the products.

  The transformer can also separate the reagents from the reactants for a mixed

  training mode. This can be toggled (default True) by setting the value of

  sep_reagent while calling the transformer.

  Examples

  -----

  --------

  Note

  -----

  ----

  This class only transforms the feature field of a reaction dataset like USPTO.

  """

  def __init__(self, sep_reagent: bool = True, dataset: Optional[Dataset] = None):

  def __init__(self,

               sep_reagent: bool = True,

               dataset: Optional[Dataset] = None):

    """Initializes the Reaction split Transformer.

    Parameters