def _get_normals(v):
not_v = np.array([<NUM_LIT:1>, <NUM_LIT:0>, <NUM_LIT:0>])<EOL>if np.all(np.abs(v) == not_v):<EOL><INDENT>not_v = np.array([<NUM_LIT:0>, <NUM_LIT:1>, <NUM_LIT:0>])<EOL><DEDENT>n1 = np.cross(v, not_v)<EOL>n1 /= norm(n1)<EOL>n2 = np.cross(v, n1)<EOL>return n1, n2<EOL>
get two vectors that form a basis w/ v

    Note: returned vectors are unit