Caffeine extraction from tea experiment? azeotropic drying?

In the caffeine experiment, some students got a cloudy distillate when they removed the CH2Cl2 (dichloromethane) prior to sublimation. The cloudiness was actually due to the presence of water in the distillate, and what was happening was an example of "azeotropic drying". Explain what was going on?

Could anyone explain for me this question plzz... I am not quite sure about this term "azeotropic drying"?
 
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