move through lines after using readline() python

Question

I am currently attempting to parse two different types of files using python's csv module. In order to discover which file I am attempting to parse, I have to read the first letter of the second line. Depending on what that line says, I would like to move to either line 7 or line 4 then use csv to read in the data. I read that it doesn't work to mix readline() and next() on a file object. Is there a different way to move down lines? This is my current code to give a better idea of what I am attempting:

with open(str(new_file)) as new_file:
    new_file.next()
    line2 = new_file.readline()
    # Check to see which file it is
    if line2[0] == "P":
        # Move to line 7
    else:
        # Move to line 4
    # Read in the contents of the file and get rid of whitespace
    list_of_dicts = list(csv.DictReader(new_file, delimiter = " ", skipinitialspace = True))

If anyone has an idea of how to deal with this, that would be fantastic.

Answer 1

line2 = new_file.next() # now pointing at line 3
if line2[0] == "P":
    for _ in xrange(4):
        new_file.next() # skip lines 3, 4, 5, 6
else:
    new_file.next() # skip line 3 only