Handel empty results

[DanielWarshofsky]

All functions that preform two database searches do not handle cases in which some of the results may be empty. Exit early if results are empty and print a message.

[DanielWarshofsky]

This scheme allows users to handle some empty results by getting the data from each table separately.

SCoPe_tools/SCoPe_db.py

Lines 385 to 389 in d651184

	if join:
	df=df_c.merge(df_f,on='_id')
	return df
	else:
	return df_c,df_f

Not a bullet proof solution

[DanielWarshofsky]

In this

SCoPe_tools/SCoPe_db.py

Line 198 in d320c45

ids=[_id for _id in df_c['_id']]

and other parts like it, do a check for empty results