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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 extrusion(target, throat_length='throat.length', throat_area='throat.area'):
 r""" Calculate throat volume from the throat area and the throat length. This method is useful for abnormal shaped throats. Parameters target : OpenPNM Object The object which this model is associated with. This controls the length of the calculated array, and also provides access to other necessary properties. throat_length and throat_area : strings The dictionary keys containing the arrays with the throat area and length values. Notes ----- At present this models does NOT account for the volume reprsented by the intersection of the throat with a spherical pore body. """

    leng = target[throat_length]
    area = target[throat_area]
    value = leng*area
    return value