Python datetime类函数产生错误

我正在用python 3编写一个函数，它使用photo dir条目列表pdel并生成photo name dict类型的字典，其中键是photo的文件名，值是photo类型的对象，字段大小是photo dir条目中元素的大小，字段pdate是来自照片目录条目。我编写的函数产生了一个错误：

 ## A photo-dir-entry is a list consisting of the following
 ## elements in order:
 ## - a Str representing the filename of the photo
 ## - an Int[>=1] representing the size of the photo file
 ## - an Int representing the year the photo was taken
 ## - an Int[1<=,<=12] representing the month the photo was taken
 ## - an Int[1<=,<=31] representing the day the photo was taken
 ## The Date elements contain a valid date.

 ## A photo-dir-entry-list is a list of photo-dir-entries with unique filenames.

 ## A Photo is an object consisting of two fields
 ## - size: an Int[>0] representing the size of the file
 ## - pdate: a Date representing the date the photo was taken    
 class Photo:
     'Fields: size, pdate'

 ## Purpose: constructor for class Photo
 ## __init__: Int Int Int Int -> Photo
 ## Note: Function definition needs a self parameter and does not require a return statement
def __init__(self, size, year, month, day):
    self.size = size
    self.pdate = date(year, month, day)

 ## Purpose: Produces a string representation of a Photo
 ## __repr__: Photo -> Str
def __repr__(self):
    s1 = "SIZE: " + str(self.size)
    s2 = "; DATE: " + self.pdate.isoformat()
    return s1 + s2

def create_photo_name_dict(pdel):
    ph_dict = {}
    for entry in pdel:
        ph_dict[entry[0]] = Photo(ph_dict[entry[1]], ph_dict[entry[2]],  ph_dict[entry[3]], ph_dict[entry[4]])
    return ph_dict

我最终得到了一个我应该产生的错误

{ "DSC315.JPG": Photo(55,2011,11,13),
         "DSC316.JPG": Photo(53,2011,11,12)}

错误是：

`Traceback (most recent call last):
  File "/Applications/Wing101.app/Contents/Resources/src/debug/tserver/_sandbox.py", line 2, in <module>
if __name__ == '__main__':
  File "/Applications/Wing101.app/Contents/Resources/src/debug/tserver/_sandbox.py", line 56, in create_photo_name_dict
builtins.KeyError: 55` 

在create_photo_name_dict中，当在for循环中创建dict时，您试图将参数作为ph_dict[entry[1]]等传递给photo。但是ph_dict最初是空的，所以这永远不会起作用，并且非常确定这也不是您想要的

只需输入条目[1]、`entry[2]等，我相信这也是您想要的-

ph_dict[entry[0]] = Photo(entry[1], entry[2],  entry[3], entry[4])

---

这个错误是…？一个错误？你认为你可以更具体一点吗？你希望ph_dict[entry[1]到底做什么？我希望它将datetime模块的数据结构转换为一个字典

ph_dict[entry[0]] = Photo(entry[1], entry[2],  entry[3], entry[4])