How can i fix this error so i can open the file properly?

I am trying to open a file with these two functions.

def readFastaFile(filename):
  """
  Read a fasta file (filename) from disk and return
  its full contents as a string
  """
  inf=open(filename)
  data=inf.read()
  inf.close()
  return data

fastarec = readFastaFile('ins.fasta')

def printTableFromFasta(fastarec):
  infile = open(fastarec)
  sequences = infile.read()
  infile.close()

I get an error every time I try to run it:

Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "C:\ProgramData\Anaconda3\lib\site-packages\spyder\utils\site\sitecustomize.py", line 880, in runfile
    execfile(filename, namespace)
    File "C:\ProgramData\Anaconda3\lib\site-packages\spyder\utils\site\sitecustomize.py", line 102, in execfile
    exec(compile(f.read(), filename, 'exec'), namespace)
    File "C:/Users/20183279/Documents/programmeren/huiswerkopgave3.py", line 32, in <module>
    printTableFromFasta(fastarec)
    File "C:/Users/20183279/Documents/programmeren/huiswerkopgave3.py", line 19, in printTableFromFasta
    infile = open(fastarec) FileNotFoundError: [Errno 2] No such file or directory: '>NM_001185098.1 Homo sapiens insulin (INS), transcript variant 3, mRNA \nAGCCCTCCAGGACAGGCTGCATCAGAAGAGGCCATCAAGCAGGTCTGTTCCAAGGGCCTTTGCGTCAGGT
\nGGGCTCAGGATTCCAGGGTGGCTGGACCCCAGGCCCCAGCTCTGCAGCAGGGAGGACGTGGCTGGGCTCG
TGAAGCATGTGGGGGTGAGCCCAGGGGCCCCAAGGCAGGGCACCTGGCCTTCAGCCTGCCTCAGCCCTGC
CTGTCTCCCAGATCACTGTCCTTCTGCCATGGCCCTGTGGATGCGCCTCCTGCCCCTGCTGGCGCTGCTG
GCCCTCTGGGGACCTGACCCAGCCGCAGCCTTTGTGAACCAACACCTGTGCGGCTCACACCTGGTGGAAG
CTCTCTACCTAGTGTGCGGGGAACGAGGCTTCTTCTACACACCCAAGACCCGCCGGGAGGCAGAGGACCT
GCAGGTGGGGCAGGTGGAGCTGGGCGGGGGCCCTGGTGCAGGCAGCCTGCAGCCCTTGGCCCTGGAGGGG
TCCCTGCAGAAGCGTGGCATTGTGGAACAATGCTGTACCAGCATCTGCTCCCTCTACCAGCTGGAGAACT
ACTGCAACTAGACGCAGCCCGCAGGCAGCCCCACACCCGCCGCCTCCTGCACCGAGAGAGATGGAATAAA
GCCCTTGAACCAGCAAAA\n'

Why do I get the FileNotFoundError?