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

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)