<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _build_coeff_matrix(degree, knotvector, params, points):
 """ Builds the coefficient matrix for global interpolation. This function only uses data points to build the coefficient matrix. Please refer to The NURBS Book (2nd Edition), pp364-370 for details. :param degree: degree :type degree: int :param knotvector: knot vector :type knotvector: list, tuple :param params: list of parameters :type params: list, tuple :param points: data points :type points: list, tuple :return: coefficient matrix :rtype: list """

    # Number of data points
    num_points = len(points)

    # Set up coefficient matrix
    matrix_a = [[0.0 for _ in range(num_points)] for _ in range(num_points)]
    for i in range(num_points):
        span = helpers.find_span_linear(degree, knotvector, num_points, params[i])
        matrix_a[i][span-degree:span+1] = helpers.basis_function(degree, knotvector, span, params[i])

    # Return coefficient matrix
    return matrix_a