9-2 analyze the character distribution of a document (20 分)
download the attachment, edit the test.py file in the src/ directory, read the contents of the sample.txt file, analyze the character distribution of the lowercase letters a-z, count the total number of characters in the file, and output the result in alphabetical order to result.txt file.
notice:
(1) Ignore upper and lower case, i.e. upper case A and lower case a are treated as the same letter.
(2) Only alphanumeric characters are counted, other characters including spaces are not considered.
(3) After finishing your code, compress the src folder into a src.zip file and upload it.
sample.txt
I have a Dream
I have a dream that one day this nation will rise up and live out the true meaning of its creed: "We hold these truths to be self evident that all men are created equal!".
I have a dream that one day on the red hills of Georgia, the sons of former slaves and the sons of former slave owners will be able to sit down together at the table of brotherhood.
I have a dream that one day even the state of Mississippi, a state sweltering with the heat of injustice, sweltering with the heat of oppression, will be transformed into an oasis of freedom and justices.
I have a dream today.
result.txt
There are a total of 467 characters, where each letter is distributed as follows:
a:46, b:6, c:4, d:21, e:69, f:14, g:6, h:29, i:32, j:2, l:20,