code: @Nonnull
    public CSSSimpleValueWithUnit setValue (@Nonnull final BigDecimal aValue)
    {
      m_aValue = ValueEnforcer.notNull (aValue, "Value");
      return this;
    }
docs: Set the numerical value.
  
  @param aValue
  The new value to set. May not be <code>null</code>.
  @return this
  @since 3.7.3