Project: s41467-025-62292-x | Function: find_tas (python)

system: You are an expert Python programmer implementing algorithms from scientific papers.
Complete the masked function based on the algorithm description.
Follow Python best practices and maintain consistent code style.
Return **only** the complete Python function code.

user: Complete this Python function:

**DESCRIPTION:** Implements the core TA dinucleotide site identification algorithm that systematically scans genomic sequences to locate all TA sites where transposons can insert, which is essential for transposon sequencing (Tn-seq) analysis of gene essentiality across different host environments

**KEY TERMS:** {
  "fasta": "genomic sequence file for TA site identification",
  "ct": "position counter for tracking genomic coordinates",
  "looking": "state variable for detecting TA dinucleotide pattern",
  "acc": "sequence accession identifier",
  "TA": "dinucleotide target sites for transposon insertion"
}

**CONTEXT CODE:** # Goal: Make a list of the TA sites in a nucleotide fasta file

import glob 

def find_tas(fasta):
	raise NotImplementedError("find_tas function has been masked for testing purposes")
				
# # RUN
if __name__=="__main__": 
	fastas = glob.glob("*.fasta")
	for f in fastas: 
		find_tas(f)

Complete the function implementation replacing "raise NotImplementedError".