def METHOD_NAME(val_exc, val_inh, num_pops):
    """Creates a matrix for excitatory and inhibitory values.
    Parameters
    ----------
    val_exc
        Excitatory value.
    val_inh
        Inhibitory value.
    num_pops
        Number of populations.
    Returns
    -------
    matrix
        A matrix of of size (num_pops x num_pops).
    """
    matrix = np.zeros((num_pops, num_pops))
    matrix[:, 0:num_pops:2] = val_exc
    matrix[:, 1:num_pops:2] = val_inh
    return matrix