<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def getoneblock(astr, start, end):
 """get the block bounded by start and end doesn't work for multiple blocks"""

    alist = astr.split(start)
    astr = alist[-1]
    alist = astr.split(end)
    astr = alist[0]
    return astr