Can you explain the analogy of the swan separating milk from water in the context of choosing between worldly and spiritual paths?

The analogy of the swan, or Maral, is used to illustrate how a wise person should navigate life's choices. Chapter 17 states that just as milk and water can be mixed, so too are Shreya (the good/spiritual) and Preya (the pleasant/worldly) blended in our lives. A swan is said to have the unique ability to drink only the pure milk, leaving the water behind. Similarly, the text encourages us to be like the swan. A courageous, intelligent, and wise person uses their power of discrimination to separate and cling only to Shreya, the 'milk' of pure knowledge and salvation, while turning away from and discarding the 'water' of Preya, which represents worldly attachments and ignorance.