<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_attr(obj, attr, default=None):
 """Recursive get object's attribute. May use dot notation. 4 1 """

    if '.' not in attr:
        return getattr(obj, attr, default)
    else:
        L = attr.split('.')
        return get_attr(getattr(obj, L[0], default), '.'.join(L[1:]), default)