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Given the following text description, write Python code to implement the functionality described below step by step
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Description:
 Mock QA
This notebook visualizes the default set of mocks currently (as of 2018 August) being used in the DESI Data Challenges.
Step1:  Dark-time targets
Step2:  Bright-time extragalactic targets
Step3:  Bright-time stellar targets
Step4:  Sky targets
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Python Code:
import os
import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns
sns.set(style='white', font_scale=1.1, palette='Set2')
Explanation: Mock QA
This notebook visualizes the default set of mocks currently (as of 2018 August) being used in the DESI Data Challenges.
End of explanation
from desitarget.mock.mockmaker import QSOMaker, LYAMaker, LRGMaker, ELGMaker
for Maker in (QSOMaker, LYAMaker, LRGMaker, ELGMaker):
    M = Maker()
    data = M.read()
    M.qamock_sky(data)
Explanation: Dark-time targets: QSOs (tracer & Lya), LRGs, and ELGs
(Note that there's a bug in the Lya densities that needs to be tracked down.)
End of explanation
from desitarget.mock.mockmaker import BGSMaker
M = BGSMaker()
data = M.read(only_coords=True)
M.qamock_sky(data)
Explanation: Bright-time extragalactic targets: BGS
End of explanation
from desitarget.mock.mockmaker import MWS_NEARBYMaker, WDMaker
for Maker in (MWS_NEARBYMaker, WDMaker):
    M = Maker()
    data = M.read()
    M.qamock_sky(data, nozhist=True)
Explanation: Bright-time stellar targets: MWS/100 pc and MWS/WD
End of explanation
from desitarget.mock.mockmaker import SKYMaker
M = SKYMaker()
data = M.read()
M.qamock_sky(data, nozhist=True)
Explanation: Sky targets
End of explanation
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