new_contents: '''
  __init__.py is automatically run with the Python command 'import willowtree'.
  
  The notation 'from .<module> import <attribute>' reads: search for <module> in
  the current directory (.) and import <attribute>.
  
  <attribute> will now be available to call as willowtree.<attribute>, instead
  of as willowtree.<module>.<attribute>.
  
  For example, on Terminal or Command Window the following commands will both
  run function maketree:
  
  $ python3
  >>> import willowtree
  >>> willowtree.maketree()
  
  or, using wt as an alias:
  
  >>> import willowtree as wt
  >>> wt.maketree()
  
  which is obviously less burdensome than willowtree.maketree.maketree().
  '''
  import time
  import numpy as np
  from scipy import stats, optimize
  import matplotlib.pyplot as plt
  import seaborn as sns
  
  from .__version__ import __version__
  from .maketree import maketree
  from .sampling import sampling
  from .lp import lp
  from .graph import graph
  
subject: Add __init__.py to 'willowtree' directory