Answer:
An extract from the answer is as follows:
 for i in salary:
 total_salary+=float(i)
 count+=1 
 return round(total_salary/count,2)
def getMonth(date):
 ddate = []
 for i in date:
 ddate.append(i.split('/')[0])
 mode = int(max(set(ddate), key=ddate.count))
 return mode 
def highestHireMonth(filename):
 month = []
See explanation for further details
Step-by-step explanation:
Given
Attachment 1 completes the question
The complete answer could not be submitted. So, I've added it as an attachment.
See attachment 2 for program source file which includes the main method.
Comments are used to explain difficult lines