human
Can you provide a the Python program you requested given the following:
Complete the below
def expr_to_tree(ind, pset):

    ''''Convert the unstructured DEAP pipeline into a tree data-structure.
    Parameters
    ind: deap.creator.Individual
    The pipeline that is being exported
    Returns
    pipeline_tree: list
    List of operators in the current optimized pipeline
    EXAMPLE:
    pipeline:
    "DecisionTreeClassifier(input_matrix, 28.0)"
    pipeline_tree:
    [\'DecisionTreeClassifier\', \'input_matrix\', 28.0]'
    '''
assistant
#Here is the Python program you requested.
    def prim_to_list(prim, args):
        if isinstance(prim, deap.gp.Terminal):
            if (prim.name in pset.context):
                return pset.context[prim.name]
            else:
                return prim.value
        return ([prim.name] + args)
    tree = []
    stack = []
    for node in ind:
        stack.append((node, []))
        while (len(stack[(-1)][1]) == stack[(-1)][0].arity):
            (prim, args) = stack.pop()
            tree = prim_to_list(prim, args)
            if (len(stack) == 0):
                break
            stack[(-1)][1].append(tree)
    return tree