Python merge two dicts

merge-dicts.py

def merge(a, b):
    c = {}
    for k in a:
        c[k] = a[k]

    for k in b:
        if k in c:
            v1 = c[k]
            v2 = b[k]
            if isinstance(v1, dict) and isinstance(v2, dict):
                c[k] = merge(v1, v2)
            else:
                c[k] = v2
        else:
            c[k] = b[k]

    return c