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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 _get_task_priority(tasks, task_priority):
 """Get the task `priority` corresponding to the given `task_priority`. If `task_priority` is an integer or 'None', return it. If `task_priority` is a str, return the priority of the task it matches. Otherwise, raise `ValueError`. """

    if task_priority is None:
        return None
    if is_integer(task_priority):
        return task_priority
    if isinstance(task_priority, basestring):
        if task_priority in tasks:
            return tasks[task_priority].priority

    raise ValueError("Unrecognized task priority '{}'".format(task_priority))