<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def plot_string_match(sf,regex,field,**kwargs):
 """ Plot the geometry of a shapefile whose fields match a regular expression given :param sf: shapefile :type sf: shapefile object :regex: regular expression to match :type regex: string :field: field number to be matched with the regex :type field: integer """

    index,shape_records = string_match(sf,regex,field)
    plot(shape_records,**kwargs)