def setIV(self, IV):
if not IV or len(IV) != self.block_size:<EOL><INDENT>raise ValueError("<STR_LIT>" + str(self.block_size) + "<STR_LIT>")<EOL><DEDENT>IV = self._guardAgainstUnicode(IV)<EOL>self._iv = IV<EOL>
Will set the Initial Value, used in conjunction with CBC mode