private Expression parseCount(Expression expr) {
    BinaryExpression binExpr = ObjectUtil.asInstance(expr, BinaryExpression.class);
    if (binExpr == null || binExpr.getOperation().getType() != Types.MULTIPLY) return expr;
    count = binExpr.getLeftExpression();
    return binExpr.getRightExpression();
  }
If the given statement is a valid interaction definition, returns the rewritten statement.
If the given statement is not an interaction definition, returns null.
If the given statement is an invalid interaction definition, records a compile error
and returns null.
spock-core/src/main/java/org/spockframework/compiler/InteractionRewriter.java