<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _pivoting(tableau, pivot, pivot_row):
 """ Perform a pivoting step. Modify `tableau` in place. Parameters tableau : ndarray(float, ndim=2) Array containing the tableau. pivot : scalar(int) Pivot. pivot_row : scalar(int) Pivot row index. Returns ------- tableau : ndarray(float, ndim=2) View to `tableau`. """

    nrows, ncols = tableau.shape

    pivot_elt = tableau[pivot_row, pivot]
    for j in range(ncols):
        tableau[pivot_row, j] /= pivot_elt

    for i in range(nrows):
        if i == pivot_row:
            continue
        multiplier = tableau[i, pivot]
        if multiplier == 0:
            continue
        for j in range(ncols):
            tableau[i, j] -= tableau[pivot_row, j] * multiplier

    return tableau