def find_requirements(max_depth=3):
    'Returns the path of a Pipfile in parent directories.'
    i = 0
    for (c, d, f) in walk_up(os.getcwd()):
        i += 1
        if (i < max_depth):
            if 'requirements.txt':
                r = os.path.join(c, 'requirements.txt')
                if os.path.isfile(r):
                    return r
    raise RuntimeError('No requirements.txt found!')
Returns the path of a Pipfile in parent directories.
def find_requirements(max_depth=3):
    
    i = 0
    for (c, d, f) in walk_up(os.getcwd()):
        i += 1
        if (i < max_depth):
            if 'requirements.txt':
                r = os.path.join(c, 'requirements.txt')
                if os.path.isfile(r):
                    return r
    raise RuntimeError('No requirements.txt found!')