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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 strand(s1, s2):
 """ Returns the binary AND of the 2 provided strings s1 and s2. s1 and s2 must be of same length. """

    return "".join(map(lambda x,y:chr(ord(x)&ord(y)), s1, s2))