# biSearch.py

import bisect

def binSrch(elems, v):
  'Locate the leftmost value exactly equal to v'
  i = bisect.bisect_left(elems, v)
  if i != len(elems) and elems[i] == v:
    return i
  return -1


elems = [ 3, 5, 8, 19, 23, 26, 45]
print(binSrch(elems, 19))
print(binSrch(elems, 27))