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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_branch_length(self, age=None, pos=0):
 """Get the length of a branch. This method calculates the length of a branch in specific age. The used formula: length * scale^age. Args: age (int):
 The age, for which you want to know the branch length. Returns: float: The length of the branch """

        if age is None:
            age = self.age

        return self.length * pow(self.branches[pos][0], age)