class_docstr: Represents a tensor of time periods.
class_docstr_tok: ["Represents","a","tensor","of","time","periods","."]
docstr: Adds another PeriodTensor of the same type.
docstr_tok: ["Adds","another","PeriodTensor","of","the","same","type","."]
code: def __add__(self, other):
      """Adds another PeriodTensor of the same type."""
      if other.period_type() != self._period_type:
          raise ValueError(
              "Mixing different period types is not supported"
          )
  
      return PeriodTensor(
          self._quantity + other.quantity(), self._period_type
      )
  
imports: import tensorflow.compat.v2
  from tf_quant_finance.datetime import constants
  from tf_quant_finance.datetime import tensor_wrapper
label_desc: Use image node_id 5 for calling the PeriodTensor obj's underlying member method code with example usage: obj.__add__(other) and returns: PeriodTensor