def download_all(count_of_eshops=30, req=None):
"""
A function for downloading it all-at-once.
:param RequestHelper req: a Request helper class to be passed
:param int count_of_eshops: Number of eshops to include.
:return pandas.DataFrame: Data frame with all the data
"""
# we run the Heureka first
h = Heureka(req=req)
h.run(count_of_eshops)
# then we find the instagram links on the eshop's webpages
e = EshopWebsite(req=req)
e.run([shop['link'] for shop in h.output])
# then use the information from web pages to collect instagram accounts
i = Instagram(req=req)
i.run([shop['instagram'] for shop in e.output if shop['instagram']])
# here we create DataFrames
df_h = pd.DataFrame(h.output).set_index('link')
df_e = pd.DataFrame(e.output).set_index('url')
df_i = pd.DataFrame(i.output).set_index('account')
df_all = df_h.join(pd.merge(df_e, df_i, left_on='instagram', right_index=True))
# and return the merged DataFrame
return df_all
