def delete(ename):
"""
Deletes the expression with given name if it exists.
"""
if exists(ename):
try:
visit.DeleteExpression(ename)
except:
# must be a database expression
pass
def clear():
"""
Deletes all existing expressions.
"""
expr_names = [expr[0] for expr in visit.Expressions()]
for ename in expr_names:
try:
visit.DeleteExpression(ename)
except:
# must be a database expression
pass
