input: def compute_average_salary(filename: str) -> float:
      """
      Compute the average salary of entries in a CSV file with a 'name' and 'salary' header.
      
      >>> compute_average_salary('salary.csv')
      2000.0
      """
output:     
      import csv
  
      total_salary = 0
      count = 0
  
      with open(filename, newline='') as csvfile:
          reader = csv.DictReader(csvfile)
          for row in reader:
              total_salary += float(row['salary'])
              count += 1
  
      return total_salary / count if count > 0 else 0.0
  