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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 _antisymm_12(C):
 """To get rid of NaNs produced by _scalar2array, antisymmetrize the first two indices of operators where C_ijkl = -C_jikl"""

    nans = np.isnan(C)
    C[nans] = -np.einsum('jikl', C)[nans]
    return C