file_obj.read function requires number of bytes to be read as mandatory argument

[Prakash2403]

Example:

Executing

# This raises error
with open('sample.txt') as f:
    data = f.read()

raises an error saying error: missing argument 'sz'. However, when the number of bytes to be read is passed explicitly, it works as expected

# This returns first 100 bytes
with open('sample.txt') as f:
    data = f.read(100)

Ideal Behaviour

If nothing is passed, the whole file should be read and returned.

Possible fix
Assumption: internal/file.seq handles all file operations (read in this case)

Need to make sz and Optional parameter here. And if sz is None, then set sz to the file size.