Simple 1 octave piano in Python with live input

piano.py

import numpy as np
import simpleaudio as sa
import os, sys, termios, time, tty

# Key mapping:
#  W E   T I U
# A S D F G H J K
#
# Which translates to:
#  C#D#  F#G#A#
# C D E F G A B C
#
# Press = or + to increase tone duration,
# - or _ to decrease, x or X to exit.

seconds = .2

def _synth(f):
    frequency = int(f)
    t = np.linspace(0, seconds, seconds * 44100, False)
    note = np.sin(frequency * t * 2 * np.pi)
    audio = note * (2**15 - 1) / np.max(np.abs(note))
    audio = audio.astype(np.int16)
    play_obj = sa.play_buffer(audio, 1, 2, 44100)
    play_obj.wait_done()


def _getInput():
   fd = sys.stdin.fileno()
   old_settings = termios.tcgetattr(fd)
   try:
      tty.setraw(fd)
      ch = sys.stdin.read(1)
   finally:
      termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
   print(ch)
   return ch


while True:
    try:
        pressed = _getInput()

        if pressed in ("=" or "+"):         # Increase tone duration
            seconds += .1
            print(seconds)

        elif pressed in ("-" or "_"):       # Decrease tone duration
            seconds -= .1
            if seconds <= 0:                # Don't allow the time to go to 0
                seconds = .1
            print(seconds)

        elif pressed in ("x" or "X"):       # Press X to exit
            sys.exit()

        elif pressed == "a": _synth(261.63) # C
        elif pressed == "w": _synth(277.18) # C#
        elif pressed == "s": _synth(293.66) # D
        elif pressed == "e": _synth(311.13) # D#
        elif pressed == "d": _synth(329.63) # E
        elif pressed == "f": _synth(349.23) # F
        elif pressed == "t": _synth(369.99) # F#
        elif pressed == "g": _synth(392)    # G
        elif pressed == "y": _synth(415.3)  # G#
        elif pressed == "h": _synth(440)    # A
        elif pressed == "u": _synth(466.16) # A#
        elif pressed == "j": _synth(493.88) # B
        elif pressed == "k": _synth(523.25) # C

        else:
            pass

    except:
        if pressed in ("x", "X"): print("Exiting..."); sys.exit()