d1 = fil.read('file.json')   # Any Json
d2 = fil.read('file.toml')   # A dict
d3 = fil.read('file.yaml')   # Any JSON
d4 = fil.read('file.txt')    # A string

# Reading a JSON Line file returns an interator:
for record in fil.read('file.jsonl'):
    print(record)  # A sequence of JSON

fil.write(d1, 'file.json')  # d1 can be any JSON
fil.write(d2, 'file.toml')  # d2 must be a dict
fil.write(d3, 'file.yaml')  # d3 can be any JSON
fil.write(d4, 'file.txt')   # d4 most be a str

# Write an iterator to a JSON Line file
dicts = ({'key': i} for i in range(10))
fil.write(dicts, 'file.jsonl')