<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def getvar(root, name, vtype='', dimensions=(), digits=0, fill_value=None, source=None):
 """ Return a variable from a NCFile or NCPackage instance. If the variable doesn't exists create it. Keyword arguments: root -- the root descriptor returned by the 'open' function name -- the name of the variable vtype -- the type of each value, ex ['f4', 'i4', 'i1', 'S1'] (default '') dimensions -- the tuple with dimensions name of the variables (default ()) digits -- the precision required when using a 'f4' vtype (default 0) fill_value -- the initial value used in the creation time (default None) source -- the source variable to be copied (default None) """

    return root.getvar(name, vtype, dimensions, digits, fill_value, source)