Write a function that flattens an `Array` of `Array` objects into a flat `Array`.  Your function must only do one level of flattening.

```python
flatten [1,2,3] # => [1,2,3]
flatten [[1,2,3],["a","b","c"],[1,2,3]]  # => [1,2,3,"a","b","c",1,2,3]
flatten [[[1,2,3]]] # => [[1,2,3]]
```

Difficulty: introductory

Starter code:

def flatten(lst):
	

Solutions:
def flatten(lst):
    r = []
    for x in lst:
       if type(x) is list:
          r.extend(x)
       else:
          r.append(x)
    return r 

def flatten(lst):
    return sum(([i] if not isinstance(i, list) else i for i in lst), [])

from itertools import chain
def flatten(lst):
    try:
        return list(chain.from_iterable(lst))
    except:
        return lst

from itertools import chain

def flatten(lst):
    try:
        return list(chain(*lst))
    except TypeError:
        return lst

def flatten(lst):
    #your code here\
    res = []
    for i in lst:
      if isinstance(i, list):
        res.extend(i)
      else:
        res.append(i)
    return res

def flatten(lst):
    return [item for sublist in [seq if isinstance(seq, list) else [seq] for seq in lst] for item in sublist]

def flatten(lst):
    return sum((([x], x)[isinstance(x, list)] for x in lst), [])

def flatten(lst):
    res = []
    for l in lst:
        if isinstance(l, list):
            res.extend(l)
        else:
            res.append(l)
    return res

def flatten(lst):
    return [x for xs in lst for x in (xs if isinstance(xs, list) else [xs])]

def flatten(a):
    return [x for b in a for x in (b if type(b) is list else [b] ) ]