def round_family(family, num_digits=3):
    """Round the matrix coefficients of a family to specified significant digits.

    Parameters
    -----------
    family: iterable of Model objects that represents
        a family.
    num_digits: integer
        Number if significant digits to which the matrix coefficients are rounded.

    Returns
    ----------
    A list of Model objects representing the family, with
    the matrix coefficients rounded to num_digits significant digits.

    """
    return [member.around(num_digits) for member in family]