#!/usr/bin/env python

#find the indices of all matching values in a list
def find_matches(l, val):
    i = -1
    indices = []
    try:
        while 1:
            i = l.index(val, i+1)
            indices.append(i)
    except ValueError:
        pass
    return(indices)

#flatten a list of lists into a list of elements
def flatten_list(l):
    fl = [item for sublist in l for item in sublist]
    return(fl)