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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 logp_gradient_of_set(variable_set, calculation_set=None):
 """ Calculates the gradient of the joint log posterior with respect to all the variables in variable_set. Calculation of the log posterior is restricted to the variables in calculation_set. Returns a dictionary of the gradients. """


    logp_gradients = {}
    for variable in variable_set:
        logp_gradients[variable] = logp_gradient(variable, calculation_set)

    return logp_gradients