import math


def get_line_ori(x_0, y_0, x_1, y_1):
    """Returns the orientation of a vector defined by two points in 2D space.

    Parameters
    ----------
    x_0 : float
        X coordinate of first point
    y_0 : float
        Y coordinate of first point
    x_1 : float
        X coordinate of second point
    y_1 : float
        Y coordinate of second point

    Returns
    -------
    float
        Orientation of the vector (radians)

    """
    
    return math.atan2(y_1-y_0, x_1-x_0)