'''Run this cell please'''

import random

def create_gene(n):

'''Creates random DNA sequence of length n.

Arguments:

n: length of DNA sequence

Result:

returns DNA sequence

'''

return ''.join([random.choice('ATGC') for _ in range(n)])

def write_fasta(header,seq,fileout):

'''Writes a FASTA file.

Arguments:

header: FASTA header

seq: sequence

Result:

writes fasta file

'''

with open(fileout,'w') as outfile: #this is a context manager that opens and closes the file

outfile.write('{} '.format(header))

outfile.write('{} '.format(seq))

#create FASTA files

amount_of_files = 20

for num in range(amount_of_files):

header = '{} {}'.format('>gene',num+1)

filename = '{}_{}.fasta'.format('sequence',num+1)

random_gene = create_gene(random.randint(50,100))

write_fasta(header,random_gene,filename)

1. how to create a function that counts the number of codons in each sequence from the FASTA files. Which fasta file has the sequence with the most occurances of ATG?