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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 _flip_sign_row(self, i):
 """Multiply -1 for all elements in row"""


        L = np.eye(3, dtype='intc')
        L[i, i] = -1
        self._L.append(L.copy())
        self._A = np.dot(L, self._A)