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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_default_branch(repo):
 """returns the name of the default branch of the repo"""

    url = "{}/repos/{}".format(GITHUB_API_BASE, repo)
    response = requests.get(url)
    if response.status_code == 200:
        api_response = json.loads(response.text)
        return api_response['default_branch']
    else:
        return 'master'