how to create low pass filter / high pass filter for a signal using sinc function with a signal x given and parameters alpha <1 and beta>1 in python

Question

i can use numpy and scipy without scipy.butter i am given a signal and i neet to filter it. i need to extract the frequencies and create low-pass, high pass filter ,and band pass filter i have started like this

def LPF(x,alpha):
    """
    returns the signal x filtered with cutoff alpha
    :param x: 1D vector
    :param alpha: scalar, <1
    :return: the filtered vector x
    """

def HPF(x,alpha):
    """
    returns the signal x filtered with cutoff alpha
    :param x: 1D vector
    :param beta: scalar, >1
    :return: the filtered vector x
    """