code: public UnicodeSet applyPropertyAlias(String propertyAlias, String valueAlias) {
          return applyPropertyAlias(propertyAlias, valueAlias, null);
      }
docs: Modifies this set to contain those code points which have the
  given value for the given property.  Prior contents of this
  set are lost.
  
  @param propertyAlias a property alias, either short or long.
  The name is matched loosely.  See PropertyAliases.txt for names
  and a description of loose matching.  If the value string is
  empty, then this string is interpreted as either a
  General_Category value alias, a Script value alias, a binary
  property alias, or a special ID.  Special IDs are matched
  loosely and correspond to the following sets:
  
  "ANY" = [\\u0000-\\u0010FFFF],
  "ASCII" = [\\u0000-\\u007F].
  
  @param valueAlias a value alias, either short or long.  The
  name is matched loosely.  See PropertyValueAliases.txt for
  names and a description of loose matching.  In addition to
  aliases listed, numeric values and canonical combining classes
  may be expressed numerically, e.g., ("nv", "0.5") or ("ccc",
  "220").  The value string may also be empty.
  
  @return a reference to this set