code: public VariableExpression getVariableExpression() {
          Expression leftExpression = this.getLeftExpression();
  
          return leftExpression instanceof VariableExpression
                      ? (VariableExpression) leftExpression
                      : null;
      }
docs: This method returns the left hand side of the declaration cast to the VariableExpression type.
  This is an unsafe method to call. In a multiple assignment statement, the left hand side will
  be a TupleExpression and a ClassCastException will occur. If you invoke this method then
  be sure to invoke isMultipleAssignmentDeclaration() first to check that it is safe to do so.
  If that method returns true then this method is safe to call.
  
  @return left hand side of normal variable declarations
  @throws ClassCastException if the left hand side is not a VariableExpression (and is probably a multiple assignment statement).