code: def from_list(cls, terms_list, coefficient=1.0):
          
          if not all([isinstance(op, tuple) for op in terms_list]):
              raise TypeError("The type of terms_list should be a list of (name, index) "
                              "tuples suitable for PauliTerm().")
  
          pterm = PauliTerm("I", 0)
          assert all([op[0] in PAULI_OPS for op in terms_list])
  
          indices = [op[1] for op in terms_list]
          assert all(_valid_qubit(index) for index in indices)
  
          # this is because from_list doesn't call simplify in order to be more efficient.
          if len(set(indices)) != len(indices):
              raise ValueError("Elements of PauliTerm that are allocated using from_list must "
                               "be on disjoint qubits. Use PauliTerm multiplication to simplify "
                               "terms instead.")
  
          for op, index in terms_list:
              if op != "I":
                  pterm._ops[index] = op
          if not isinstance(coefficient, Number):
              raise ValueError("coefficient of PauliTerm must be a Number.")
          pterm.coefficient = complex(coefficient)
          return pterm
docs: Allocates a Pauli Term from a list of operators and indices. This is more efficient than
          multiplying together individual terms.
  
          :param list terms_list: A list of tuples, e.g. [("X", 0), ("Y", 1)]
          :return: PauliTerm