How to use the bamnostic.bai function in bamnostic

that share the same bin. A `Chunk` object in the context of
        this function is a `namedtuple` that contains the virtual offsets
        for the beginning and end of each of these chunks.

        Note: a special case of a chunk is in any Bin labeled as 37450.
        These bins always contain 2 chunks that provide the statistics
        of the number of reads that are unmapped to that reference.

        Args:
            n_chunks (int): number of chunks to be unpacked from stream

        Returns:
            chunks (list): a list of Chunk objects with the attributes of
                            chunks[i] are .voffset_beg and voffset_end
        """
        chunks = [bai.Chunk(self._io) for chunk in range(n_chunks)]
        return chunks

n_int (int): number of bins to be unpacked from stream

        Returns:
            bins (None | dict): None if just indexing the index file or a dictionary
                                of `bin_id: chunks` pairs
        Raises:
            AssertionError (Exception): if bin 37450 does not contain 2 chunks exactly
        """
        bins = None if idx else {}

        for b in range(n_bins):
            bin_id, loffset, n_chunks = unpack_bid_loffset_nchunk(self._io.read(16))
            if idx:
                if bin_id == self._UNMAP_BIN:
                    assert n_chunks == 2, 'Bin 3740 is supposed to have 2 chunks. This has {}'.format(n_chunks)
                    unmapped = bai.Unmapped(*unpack_unmapped(self._io.read(32)))
                    self.unmapped[ref_id] = unmapped
                else:
                    if not n_chunks == 0:
                        self._io.seek(16 * n_chunks, 1)
            else:
                chunks = self.get_chunks(n_chunks)
                bins[bin_id] = CsiBin(loffset, chunks)
        else:
            return bins

if _PY_VERSION[0] == 2:
    from io import open
else:
    from functools import lru_cache

import bamnostic
from bamnostic import bai
from bamnostic.utils import *


def format_warnings(message, category, filename, lineno, file=None, line=None):
    return ' {}:{}: {}:{}'.format(filename, lineno, category.__name__, message)


warnings.formatwarning = bai.format_warnings


# Helper compiled structs
unpack_chunk = bai.unpack_chunk
unpack_bid_loffset_nchunk = struct.Struct('

import bamnostic
from bamnostic import bai
from bamnostic.utils import *


def format_warnings(message, category, filename, lineno, file=None, line=None):
    return ' {}:{}: {}:{}'.format(filename, lineno, category.__name__, message)


warnings.formatwarning = bai.format_warnings


# Helper compiled structs
unpack_chunk = bai.unpack_chunk
unpack_bid_loffset_nchunk = struct.Struct('