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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_callproc_signature(self, name, param_types):
 """Returns a procedure's signature from the name and list of types. :name: the name of the procedure :params: can be either strings, or 2-tuples. 2-tuples must be of the form (name, db_type). :return: the procedure's signature """

    if isinstance(param_types[0], (list, tuple)):
      params = [self.sql_writer.to_placeholder(*pt) for pt in param_types]
    else:
      params = [self.sql_writer.to_placeholder(None, pt) for pt in param_types]

    return name + self.sql_writer.to_tuple(params)