def record_per_row(self):
    """
    Writes a CSV file with as many records as the size of any of the lists
    A record is a row in the file, with three columns, corresponding to
    a name, salary, and position.
    """

• Create 3-field records from the three attributes such that
  • a record has elements at the same position in the three lists.
• Format a record as a string with the three elements separated by comma
• Write each record to the nba.txt text file

We use the accumulation pattern with accumulator nba_file

• Iteration is over three sequences simultaneously, the class attributes
  • three loop variables nme, slr, pos get hold of elements in self.names, self.salaries, self.positions which have the same positions
  • we use zip() built-in function to allow for parallel processing
  • we assemble string representations of the elements including the commas and store in nba_row string local variable
  • we write nba_row to the file object accumulator nba_file

###names_by_pos()

def names_by_pos(self):
    """
    Returns a dictionary with the keys are set to the names of the positions
    and the values are set to lists of each name that is that position
    """

• Initializes a dictionary sort_by_pos, which will be returned at the end of the method
• Uses an accumulation pattern with the accumulator sort_by_pos
• Iterates over two loop variables, nme and pos using the elements from self.names, and self.positions, respectively
• uses an if statement to check if pos is a key in sort_by_pos
  • if it is, it will add nme to the list set as the value attached to pos
  • if it isn't, it will add pos as a key in sort_by_pos, and then a list containing nme as the attached values
• afterwards, the method will return sort_by_pos

###most_played_position()

def most_played_position(self):
      """
      Calls names_by_pos(), and uses the returned dictionary to find the
      number of players in each position, before returning a dictionary with
      the key being the position and the value being the number of players
      with that position
      """

• Initializes a dictionary pos_and_nme with the value of self.names_by_pos()
• Initializes a dictionary num_of_pos
• uses a for in loop to go through each key in pos_and_nme, with pos as the iterator
  • adds the key pos and sets the value to the length of the list attached to pos in pos_and_nme to num_of_pos
• Returns num_of_pos