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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 custom_operation(dbg, thread_id, frame_id, scope, attrs, style, code_or_file, operation_fn_name):
 """ We'll execute the code_or_file and then search in the namespace the operation_fn_name to execute with the given var. code_or_file: either some code (i.e.: from pprint import pprint) or a file to be executed. operation_fn_name: the name of the operation to execute after the exec (i.e.: pprint) """

    expressionValue = getVariable(dbg, thread_id, frame_id, scope, attrs)

    try:
        namespace = {'__name__': '<custom_operation>'}
        if style == "EXECFILE":
            namespace['__file__'] = code_or_file
            execfile(code_or_file, namespace, namespace)
        else:  # style == EXEC
            namespace['__file__'] = '<customOperationCode>'
            Exec(code_or_file, namespace, namespace)

        return str(namespace[operation_fn_name](expressionValue))
    except:
        pydev_log.exception()