<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def is_int_vector(l):
 r"""Checks if l is a numpy array of integers """

    if isinstance(l, np.ndarray):
        if l.ndim == 1 and (l.dtype.kind == 'i' or l.dtype.kind == 'u'):
            return True
    return False