Confused on how to use a given function for reading in FASTA file in python

  fasta, function, python

I have been given the function below and a text file containing a DNA sequence. However, I am a complete beginner and have no idea how to use these two together.

The function:

def load_fasta(f):
    seq_title = f.readline()

    s =''

    while True:
        seq_line = f.readline()
    # DEBUG    print len(seq_line.strip().lower())
        if seq_line == '':
            s += seq_line.strip().lower()
    print(seq_title,'n contains %d basesnn' % len(s))
    return (seq_title,s)

There also seems to be an issue with line 11 which states:

‘str’ object has no attribute ‘readline’

I have searched for how to fix this but can’t find a solution that works

Source: Python Questions