Given an array of integers arr. Return the number of sub-arrays with odd sum.
As the answer may grow large, the answer must be computed modulo 10^9 + 7.
 
Example 1:
Input: arr = [1,3,5]
Output: 4
Explanation: All sub-arrays are [[1],[1,3],[1,3,5],[3],[3,5],[5]]
All sub-arrays sum are [1,4,9,3,8,5].
Odd sums are [1,9,3,5] so the answer is 4.

Example 2:
Input: arr = [2,4,6]
Output: 0
Explanation: All sub-arrays are [[2],[2,4],[2,4,6],[4],[4,6],[6]]
All sub-arrays sum are [2,6,12,4,10,6].
All sub-arrays have even sum and the answer is 0.

Example 3:
Input: arr = [1,2,3,4,5,6,7]
Output: 16

Example 4:
Input: arr = [100,100,99,99]
Output: 4

Example 5:
Input: arr = [7]
Output: 1

 
Constraints:

1 <= arr.length <= 10^5
1 <= arr[i] <= 100

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

def _disabled_input(*args, **kwargs):
    raise RuntimeError("input() is disabled in callable mode")
builtins.input = _disabled_input

ns = {"__name__": "__judge__"}  # prevent if __name__ == "__main__" blocks
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = "'''\nhttps://www.youtube.com/watch?v=iTukzycJ69I\n'''\n\n\nclass Solution:\n    def numOfSubarrays(self, arr: List[int]) -> int:\n        \n        '''\n            here we are calculating prefix sum.\n            Along with that we also keep track before\n            any index i, how many prefix sum are even \n            and how many prefix sum are odd by using\n            variables evenSum and oddSum. Becuase if \n            we subtract \n            \n            *************************************\n                even value from odd answer is odd\n                and odd value from even again answer\n                is odd\n            *************************************\n            \n            This above mentioned simple 2 rules helpsto\n            keep track of required answer\n            \n            \n        '''\n        \n        evenSum=0\n        oddSum=0\n        prefSum=0\n        ans=0\n        \n        \n        for ele in arr:\n            \n            prefSum=prefSum+ele\n            \n            '''\n                prefix sum is odd\n            '''\n            if prefSum%2==1:\n                \n                ans+=evenSum+1\n                oddSum+=1\n            else:\n                ans+=oddSum\n                evenSum+=1\n                \n            \n            ans%=((10**9)+7)\n            \n            \n            \n        return ans\n                \n                \n            \n            \n            \n            \n            \n            \n            \n            \n            \n            \n            \n            \n            \n            \n            \n            \n        \n        \n        \n        \n            \n        \n        \n        \n        \n"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'numOfSubarrays'
if _fn_name:
    if "Solution" in ns:
        try:
            _obj = ns["Solution"]()
            if hasattr(_obj, _fn_name):
                _target = getattr(_obj, _fn_name)
        except Exception:
            _target = None
    if _target is None and _fn_name in ns and callable(ns[_fn_name]):
        _target = ns[_fn_name]
# Fallback: if there's exactly one user-defined function, use it
if _target is None:
    _cands = [v for k, v in ns.items() if callable(v) and getattr(v, "__module__", "") in ("__judge__", "__main__")]
    _user_funcs = [c for c in _cands if getattr(c, "__name__", "").startswith("_") is False]
    if len(_user_funcs) == 1:
        _target = _user_funcs[0]
if _target is None:
    raise RuntimeError(f"Could not resolve callable '{_fn_name}'")

_raw = sys.stdin.read().strip()
if _raw:
    _parsed = json.loads(_raw)
    if isinstance(_parsed, dict):
        _kwargs = _parsed.get("kwargs", {})
        _args = _parsed.get("args", [])
    else:
        _args, _kwargs = _parsed, {}
else:
    _args, _kwargs = [], {}
if not isinstance(_args, (list, tuple)):
    _args = [_args]
_res = _target(*_args, **_kwargs)
try:
    sys.stdout.write(repr(_res) + "\n")
except Exception:
    pass

```

Measured memory_bytes: 5380