我正在做HtDP 练习，但在练习 200上遇到问题。我按照书上说的做了，但我一直遇到同样的错误。无论我尝试什么，我总是得到这个：
read-itunes-as-list: expects a file with XML document as first argument, given "itunes.xml"
我试过更改 的名称itunes.xml和其他一些东西，但它们似乎都失败了。有人知道如何解决这个问题吗？这是我的代码（到目前为止）：
; An LTracks is one of:
; – '()
; – (cons Track LTracks)
; Example:
; (cons (make-track "Wild Child" "Enya" "A Day Without" 227996 2 (make-date 2002 7 17 3 55 14) 20 (make-date 2011 5 17 17 35 13))
; '())
;(define-struct track
; [name artist album time track# added play# played])
; A Track is a structure:
; (make-track String String String N N Date N Date)
; interpretation An instance records in order: the track's
; title, its producing artist, to which album it belongs,
; its playing time in milliseconds, its position within the
; album, the date it was added, how often it has been
; played, and the date when it was last played
; Example:
; (make-track "Wild Child" "Enya" "A Day Without" 227996 2 (make-date 2002 7 17 3 55 14) 20 (make-date 2011 5 17 17 35 13))
;(define-struct date [year month day hour minute second])
; A Date is a structure:
; (make-date N N N N N N)
; interpretation An instance records six pieces of information:
; the date's year, month (between 1 and 12 inclusive),
; day (between 1 and 31), hour (between 0
; and 23), minute (between 0 and 59), and
; second (also between 0 and 59).
; Example:
; (make-date 2019 7 9 20 35 54)
; modify the following to use your chosen name
(define ITUNES-LOCATION "itunes.xml")
; LTracks
(define itunes-tracks
(read-itunes-as-tracks ITUNES-LOCATION))
并且itunes.xml：
<dict>
<key>Track ID</key><integer>442</integer>
<key>Name</key><string>Wild Child</string>
<key>Artist</key><string>Enya</string>
<key>Album</key><string>A Day Without</string>
<key>Genre</key><string>New Age</string>
<key>Kind</key><string>MPEG audio file</string>
<key>Size</key><integer>4562044</integer>
<key>Total Time</key><integer>227996</integer>
<key>Track Number</key><integer>2</integer>
<key>Track Count</key><integer>11</integer>
<key>Year</key><integer>2000</integer>
<key>Date Added</key><date>2002-7-17T3:55:14</date>
<key>Play Count</key><integer>20</integer>
<key>Play Date</key><integer>3388484113</integer>
<key>Play Date UTC</key><date>2011-5-17T17:35:13
</dict>