import math


def angle(dx, dy):
    """
    Returns angle from in x- and y-coordinates.

    Parameters
    ----------
    dx : float
        x-coordinate or difference in x-coordinate.
    dy : float
        y-coordinate or difference in y-coordinate.

    Returns
    -------
    ang : float
        Corresponding angle in radians.
    """

    return math.atan2(dy, dx)